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.*;

public class Main{
	public static void main(String[] args){
		int n=ni();
		long[] a=nla(n);
		long g=a[0];
		for(int i=0;i<n;i++) g=gcd(g,a[i]);
		if(g>1){
			pl(-1);
			flush();
			return;
		}
		
		int one=0;
		int min=n+1;
		for(int i=0;i<n;i++){
			long gcd=a[i];
			int j=i;
			while((j<n) && gcd>1) gcd=gcd(gcd,a[j++]);
			if(gcd>1) continue;
			min=Math.min(min,j-i-1);
			if(a[i]==1) one++;
		}
		if(one>0){
			pl(n-one);
		}else{
			pl(n+min-1);
		}
		flush();
	}
	
	private static final byte[] buffer = new byte[1024];
	private static int ptr = 0;
	private static int buflen = 0;
	private static boolean hasNextByte() {
		if (ptr < buflen)  return true;
		else{
			ptr = 0;
			try {
				buflen = System.in.read(buffer);
			} catch (IOException e) {e.printStackTrace();}
			if (buflen <= 0)  return false;
		}
		return true;
	}
	private static int readByte() { return hasNextByte() ? buffer[ptr++] : -1;}
	private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
	private static void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;}
	public static boolean hasNext() { skipUnprintable(); return hasNextByte();}
	public static String next() {
		if (!hasNext()) throw new NoSuchElementException();
		StringBuilder sb = new StringBuilder();
		for(int b = readByte();isPrintableChar(b);b = readByte()) {
			sb.appendCodePoint(b);
		}
		return sb.toString();
	}
	public static int nextInt() {return (int)nextLong();}
	public static long nextLong() {
		if (!hasNext()) throw new NoSuchElementException();
		long n = 0;
		boolean minus = false;
		int b = readByte();
		if (b == '-') {
			minus = true;
			b = readByte();
		}
		if (b < '0' || '9' < b)  throw new NumberFormatException();
		while(true){
			if ('0' <= b && b <= '9') n = n * 10 + b-'0';
			else if(b == -1 || !isPrintableChar(b)) return minus ? -n : n;
			else throw new NumberFormatException();
			b = readByte();
		}
	}
	public static long[] nextLongArray(int i){
		long[] result=new long[i];
		for(int j=0;j<i;j++)  result[j]=nextLong();
		return result;
	}
	public static void nextLongArray(long[]... arrays){
		for(int j=0;j<arrays[0].length;j++)
			for(long[] array:arrays) array[j]=nextLong();
	}
	public static int[] nextIntArray(int i){
		int[] result=new int[i];
		for(int j=0;j<i;j++)  result[j]=nextInt();
		return result;
	}
	public static void nextIntArray(int[]... arrays){
		for(int j=0;j<arrays[0].length;j++)
			for(int[] array:arrays)  array[j]=nextInt();
	}
	public static int ni(){return nextInt();}
	public static long nl(){return nextLong();}
	public static int[] nia(int n){return nextIntArray(n);}
	public static long[] nla(int n){return nextLongArray(n);}
	public static String ne(){return next();}
	
	static StringBuilder sb=new StringBuilder();
	public static void flush(){
		System.out.print(sb);
		sb=new StringBuilder();
	}
	public static void pr(Object o){sb.append(o);}
	public static void pl(Object o){sb.append(o).append("\n");}
	public static void pl(){sb.append("\n");}
	public static int lastLowerIndex(long[] array,long lo){return lastLowerOrEqualIndex(array,lo-1);}
	public static int lastLowerOrEqualIndex(long[] array,long lo){
		int res=Arrays.binarySearch(array,lo);
		return res<0?-res-2:res;
	}
	public static long gcd(long a,long b){
		if(a>b)a%=b;
		while(a>0){
			b%=a;
			if(b==0)return a;
			a%=b;
		}
		return b;
	}
	public static long modPow(long a,long b,long mod){
		long c=1;
		while(b>0){
			if(b%2==1)  c=(c*a)%mod;
			a=(a*a)%mod;
			b/=2;
		}
		return c;
	}
	public static long inv(long a,long mod){
		long b=mod;
		long p = 1, q = 0;
		while (b > 0) {
			long c = a / b;
			long d=a;
			a = b;
			b = d % b;
			d = p;
			p = q;
			q = d - c * q;
		}
		return p < 0 ? p + mod : p;
	}
	static long time=0;
	public static void time(){
		if(time==0) time=System.nanoTime();
		else{
			long t=System.nanoTime();
			pl((t-time)/1000000000.0+"sec");
			time=t;
		}
	}
	public static Integer[] sortedIndex(long[] a){
            Integer[] res=new Integer[a.length];
            for(int i=0;i<a.length;i++)	res[i]=i;
            mergesortIndex(res,a,0,a.length);
            return res;
        }
        private static Integer[] stem=new Integer[200005];
        private static void mergesortIndex(Integer[] index,long[] a, int s, int e){//uwi's
            if(e - s <= 1)return;
            int h = s+e>>1;
            mergesortIndex(index,a, s, h);
            mergesortIndex(index,a, h, e);
            int p = 0;
            int i= s, j = h;
            for(;i < h && j < e;)stem[p++] = a[(int)index[i]] < a[(int)index[j]] ? index[i++] : index[j++];
            while(i < h)stem[p++] = index[i++];
            while(j < e)stem[p++] = index[j++];
            System.arraycopy(stem, 0, index, s, e-s);
        }
        private static long[] stmp=new long[200005];
        private static void mergesort(long[] a, int s, int e){//uwi's
            if(e - s <= 1)return;
            int h = s+e>>1;
            mergesort(a, s, h);
            mergesort(a, h, e);
            int p = 0;
            int i= s, j = h;
            for(;i < h && j < e;)stmp[p++] = a[i] < a[j] ? a[i++] : a[j++];
            while(i < h)stmp[p++] = a[i++];
            while(j < e)stmp[p++] = a[j++];
            System.arraycopy(stmp, 0, a, s, e-s);
        }
}