You have an array a with length n, you can perform operations. Each operation is like this: choose two adjacent elements from a, say x and y, and replace one of them with gcd(x, y), where gcd denotes the [greatest common divisor](https://en.wikipedia.org/wiki/Greatest_common_divisor).

What is the minimum number of operations you need to make all of the elements equal to 1?

Input

The first line of the input contains one integer n (1 ≤ n ≤ 2000) — the number of elements in the array.

The second line contains n space separated integers a1, a2, ..., an (1 ≤ ai ≤ 109) — the elements of the array.

Output

Print -1, if it is impossible to turn all numbers to 1. Otherwise, print the minimum number of operations needed to make all numbers equal to 1.

Examples

Input

5
2 2 3 4 6


Output

5


Input

4
2 4 6 8


Output

-1


Input

3
2 6 9


Output

4

Note

In the first sample you can turn all numbers to 1 using the following 5 moves:

  * [2, 2, 3, 4, 6]. 
  * [2, 1, 3, 4, 6]
  * [2, 1, 3, 1, 6]
  * [2, 1, 1, 1, 6]
  * [1, 1, 1, 1, 6]
  * [1, 1, 1, 1, 1]



We can prove that in this case it is not possible to make all numbers one using less than 5 moves.
import java.util.*;
	import java.io.*;
	import java.lang.*;
	
	public class c2
	{
		public static void main(String[] args)
		{
			InputReader in = new InputReader(System.in);
			PrintWriter pw = new PrintWriter(System.out);
		
			//Code starts..
			
			int n = in.nextInt();
			int[] a = new int[n];
			int num_1 = 0;
			for(int i=0; i<n; i++)
			{
				a[i] = in.nextInt();
				if(a[i]==1)
					num_1++;
			}
				boolean flag = false;
			int ans = n;
			int min = Integer.MAX_VALUE;
			for(int i=0; i<n; i++)
				min = Math.min(a[i], min);
			if(n>1)
			{
		
				int m = Integer.MAX_VALUE;
				int k = m;
				for(int i=0; i<n; i++)
				{
					int gcd = a[i];
					int tmp = -1;
					
					for(int j =i+1; j<n; j++)
					{
						gcd = gcd(gcd, a[j]);
						//pw.println(gcd);
						if(gcd==1)
						{
							tmp = j - i+1;
							break;
									
						}
						//pw.println(tmp);
					}
					if(tmp!=-1)
						m = Math.min(m, tmp);
				
				}
				//pw.println(m);
				if(m!=k)
					pw.println(n+m-2-num_1);
				else
					pw.println(-1);
			
			}
			else
			{
				if(a[0]==1)
					pw.println(0);
				else
					pw.println(-1);
			}
			//Code ends....
			
			
			pw.flush();
			pw.close();
		}
	
		
		static class InputReader 
		{
			 
			private final InputStream stream;
			private final byte[] buf = new byte[8192];
			private int curChar, snumChars;
			private SpaceCharFilter filter;
	 
			public InputReader(InputStream stream) 
			{
				this.stream = stream;
			}
	 
			public int snext() 
			{
				if (snumChars == -1)
					throw new InputMismatchException();
				if (curChar >= snumChars) 
				{
					curChar = 0;
					try 
					{
						snumChars = stream.read(buf);
					} 
					catch (IOException e) 
					{
						throw new InputMismatchException();
					}
					if (snumChars <= 0)
						return -1;
				}
				return buf[curChar++];
			}
	 
			public int nextInt() 
		    {
				int c = snext();
				while (isSpaceChar(c)) 
				{
					c = snext();
				}
				int sgn = 1;
				if (c == '-')
			    {
					sgn = -1;
					c = snext();
				}
				int res = 0;
				do 
				{
					if (c < '0' || c > '9')
						throw new InputMismatchException();
					res *= 10;
					res += c - '0';
					c = snext();
				} while (!isSpaceChar(c));
				return res * sgn;
			}
	 
			public long nextLong()
		    {
				int c = snext();
				while (isSpaceChar(c)) 
				{
					c = snext();
				}
				int sgn = 1;
				if (c == '-') 
				{
					sgn = -1;
					c = snext();
				}
				long res = 0;
				do 
				{
					if (c < '0' || c > '9')
						throw new InputMismatchException();
					res *= 10;
					res += c - '0';
					c = snext();
				} while (!isSpaceChar(c));
				return res * sgn;
			}
	 
			public int[] nextIntArray(int n) 
			{
				int a[] = new int[n];
				for (int i = 0; i < n; i++) 
				{
					a[i] = nextInt();
				}
				return a;
			}
	 
			public String readString()
		    {
				int c = snext();
				while (isSpaceChar(c)) 
				{
					c = snext();
				}
				StringBuilder res = new StringBuilder();
				do 
				{
					res.appendCodePoint(c);
					c = snext();
				} while (!isSpaceChar(c));
				return res.toString();
			}
	 
			public String nextLine() 
			{
				int c = snext();
				while (isSpaceChar(c))
					c = snext();
				StringBuilder res = new StringBuilder();
				do 
				{
					res.appendCodePoint(c);
					c = snext();
				} while (!isEndOfLine(c));
				return res.toString();
			}
	 
			public boolean isSpaceChar(int c) 
			{
				if (filter != null)
					return filter.isSpaceChar(c);
				return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
			}
	 
			private boolean isEndOfLine(int c) 
			{
				return c == '\n' || c == '\r' || c == -1;
			}
	 
			public interface SpaceCharFilter
		    {
				public boolean isSpaceChar(int ch);
			}
		}
		
		
		
		
		public static long mod = 1000000007;
		public static int d;
		public static int p;
		public static int q;
		
		
		public static int gcdArray(int[]a , int i, int n)
		{
			int ans = a[i];
			for(int k=i; k<n; k++) {
				ans = gcd(a[k], ans);
				if(ans==1)
					return k;
			}
			return -1;
		}
		public static  int gcd(int a, int b)
		{
		    if (a == 0)
		        return b;
		    return gcd(b%a, a);
		}
		public static int findGCD(int arr[], int n)
		{
		    int result = arr[0];
		    for (int i=1; i<n; i++)
		        result = gcd(arr[i], result);
		 
		    return result;
		}
		
	
	    public static long lcm(int[] numbers) {
	        long lcm = 1;
	        int divisor = 2;
	        while (true) {
	            int cnt = 0;
	            boolean divisible = false;
	            for (int i = 0; i < numbers.length; i++) {
	                if (numbers[i] == 0) {
	                    return 0;
	                } else if (numbers[i] < 0) {
	                    numbers[i] = numbers[i] * (-1);
	                }
	                if (numbers[i] == 1) {
	                    cnt++;
	                }
	                if (numbers[i] % divisor == 0) {
	                    divisible = true;
	                    numbers[i] = numbers[i] / divisor;
	                }
	            }
	            if (divisible) {
	                lcm = lcm * divisor;
	            } else {
	                divisor++;
	            }
	            if (cnt == numbers.length) {
	                return lcm;
	            }
	        }
	    }
		public static long fact(long n) {
			
			long factorial = 1;
			 for(int i = 1; i <= n; i++)
		        {
		            factorial *= i;
		        }
			 return factorial;
		}
		
		
		
		public static int lowerLimit(int[] a, int n) {
			int ans = 0;
			
			int ll = 0;
			int rl = a.length-1;
		//	System.out.println(a[rl]+" "+n);
			if(a[0]>n)
				return 0;
			if(a[0]==n)
				return 1;
			else if(a[rl]<=n)
				return rl+1;
		
			while(ll<=rl)
			{
				
				int mid = (ll+rl)/2;
				if(a[mid]==n)
				{
					ans = mid + 1;
					break;
				}
				
				else if(a[mid]>n)
				{
					rl = mid-1;
					
				}
				else
				{
					ans = mid+1;
					ll = mid+1;
				}
			}
			
			return ans; 
		}
		
		
		public static long choose(long total, long choose){
		    if(total < choose)
		        return 0;
		    if(choose == 0 || choose == total)
		        return 1;
		    return (choose(total-1,choose-1)+choose(total-1,choose))%mod;
		}
		
		public static int[] suffle(int[] a,Random gen)
		{
			int n = a.length;
			for(int i=0;i<n;i++)
			{
				int ind = gen.nextInt(n-i)+i;
				int temp = a[ind];
				a[ind] = a[i];
				a[i] = temp;
			}
			return a;
		}
		
		public static int floorSearch(int arr[], int low, int high, int x)
		{
		    if (low > high)
		        return -1;
		 
		    if (x > arr[high])
		        return high;
		    int mid = (low+high)/2;
		 
		 
		    if (mid > 0 && arr[mid-1] < x && x < arr[mid])
		        return mid-1;
		 
		    if (x < arr[mid])
		        return floorSearch(arr, low, mid-1, x);
		 
		    return floorSearch(arr, mid+1, high, x);
		}
		
		
		public static void swap(int a, int b){
			int temp = a;
			a = b;
			b = temp;
		}
		
		public static ArrayList<Integer> primeFactorization(int n)
		{
			ArrayList<Integer> a =new ArrayList<Integer>();
			for(int i=2;i*i<=n;i++)
			{
				while(n%i==0)
				{
					a.add(i);
					n/=i;
				}
			}
			if(n!=1)
				a.add(n);
			return a;
		}
		
		public static void sieve(boolean[] isPrime,int n)
		{
			for(int i=1;i<n;i++)
				isPrime[i] = true;
			
			isPrime[0] = false;
			isPrime[1] = false;
			
			for(int i=2;i*i<n;i++)
			{
				if(isPrime[i] == true)
				{
					for(int j=(2*i);j<n;j+=i)
						isPrime[j] = false;
				}
			}
		}
		
		public static int GCD(int a,int b)
		{
			if(b==0)
				return a;
			else
				return GCD(b,a%b);
		}
		
		public static long GCD(long a,long b)
		{
			if(b==0)
				return a;
			else
				return GCD(b,a%b);
		}
		
		public static void extendedEuclid(int A,int B)
		{
			if(B==0)
			{
				d = A;
				p = 1 ;
				q = 0;
			}
			else
			{
				extendedEuclid(B, A%B);
				int temp = p;
				p = q;
				q = temp - (A/B)*q;
			}
		}
		
		public static long LCM(long a,long b)
		{
			return (a*b)/GCD(a,b);
		}
		
		public static int LCM(int a,int b)
		{
			return (a*b)/GCD(a,b);
		}
		
		public static int binaryExponentiation(int x,int n)
		{
		    int result=1;
		    while(n>0)
		    {
		        if(n % 2 ==1)
		            result=result * x;
		        x=x*x;
		        n=n/2;
		    }
		    return result;
		}
		
		public static long binaryExponentiation(long x,long n)
		{
		    long result=1;
		    while(n>0)
		    {
		        if(n % 2 ==1)
		            result=result * x;
		        x=(x%mod * x%mod)%mod;
		        n=n/2;
		    }
		    return result;
		}
		
		public static int modularExponentiation(int x,int n,int M)
		{
		    int result=1;
		    while(n>0)
		    {
		        if(n % 2 ==1)
		            result=(result * x)%M;
		        x=(x*x)%M;
		        n=n/2;
		    }
		    return result;
		}
		
		public static long modularExponentiation(long x,long n,long M)
		{
		    long result=1;
		    while(n>0)
		    {
		        if(n % 2 ==1)
		            result=(result * x)%M;
		        x=(x*x)%M;
		        n=n/2;
		    }
		    return result;
		}
		
		public static int modInverse(int A,int M)
		{
		    return modularExponentiation(A,M-2,M);
		}
		
		public static long modInverse(long A,long M)
		{
		    return modularExponentiation(A,M-2,M);
		}
		
		public static boolean isPrime(int n)
		{
		    
		    if (n <= 1)  return false;
		    if (n <= 3)  return true;
		    
		    if (n%2 == 0 || n%3 == 0) 
		    	return false;
		 
		    for (int i=5; i*i<=n; i=i+6)
		    {
		        if (n%i == 0 || n%(i+2) == 0)
		           return false;
		    }
		    
		    return true;
		}
		
		static class pair implements Comparable<pair>
		{
			Integer x, y;
			pair(int x,int y)
			{
				this.x=x;
				this.y=y;
			}
			
			public int compareTo(pair o) {
				int result = x.compareTo(o.x);
				if(result==0)
					result = y.compareTo(o.y);
				
				return result;
			}  
			
			public String toString()
			{
				return x+" "+y;
			}
			
			public boolean equals(Object o)
			{
				if (o instanceof pair)
			    {
					pair p = (pair)o;
					return p.x == x && p.y == y ;
				}
				return false;
			}
			
			public int hashCode()
			{
				return new Long(x).hashCode()*31 + new Long(y).hashCode();
			}
		}
	}