B'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, xe2 x80 x89y), where gcd denotes the greatest common divisor. What is the minimum number of operations you need to make all of the elements equal to 1? The first line of the input contains one integer n (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x892000) -- the number of elements in the array. The second line contains n space separated integers a1, xe2 x80 x89a2, xe2 x80 x89..., xe2 x80 x89an (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89ai xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89109) -- the elements of the array. 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. In the first sample you can turn all numbers to 1 using the following 5 moves: We can prove that in this case it is not possible to make all numbers one using less than 5 moves. '...