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.
from sys import stdin
input=lambda : stdin.readline().strip()
from math import ceil,sqrt,factorial
from collections import deque
def gcd(a,b):
	a,b=max(a,b),min(a,b)
	while a%b!=0:
		a,b=b,a%b
	return b
n=int(input())
l=list(map(int,input().split()))
t=l.count(1)
if t>=1:
	print(n-t)
	exit()
else:
	z=list(l)
	a=1
	while len(z)>1:
		for i in range(len(z)-1):
			z[i]=gcd(z[i],l[i+a])
			if z[i]==1:
				print(n-1+a)
				exit()
		z.pop()
		a+=1
print(-1)