891_A. Pride
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.
```python
import math,sys,bisect,heapq,os
from collections import defaultdict,Counter,deque
from itertools import groupby,accumulate
from functools import lru_cache
#sys.setrecursionlimit(200000000)
int1 = lambda x: int(x) - 1
def input(): return sys.stdin.readline().rstrip('\r\n')
#input = iter(sys.stdin.buffer.read().decode().splitlines()).__next__
aj = lambda: list(map(int, input().split()))
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
#MOD = 1000000000 + 7
def Y(c):  print(["NO","YES"][c])
def y(c):  print(["no","yes"][c])
def Yy(c):  print(["No","Yes"][c])

def solve():
	n, = aj()
	A = aj()
	c = A.count(1)
	if c >= 1:
		print(n - c)
		exit(0)
	ans = float('inf')
	for i in range(n):
		p = A[i];t = 0
		for j in range(i+1,n):
			p = math.gcd(p,A[j])
			t += 1
			if p == 1:
				break
		if p == 1:
			ans = min(ans, n-1 + t)
	if ans == float('inf'):
		print(-1)
	else:
		print(ans)

		

















try:
	#os.system("online_judge.py")
	sys.stdin = open('input.txt', 'r') 
	sys.stdout = open('output.txt', 'w')
except:
	pass

solve()
```