Mike and gcd problem
time limit per test 2 second memory limit per test 256 megabytes
Mike has a sequence A=[a1,a2,…,an] of length n. He considers the sequence B=[b1,b2,…,bn] beautiful if the gcd of all its elements is bigger than 1, i.e. .
Mike wants to change his sequence in order to make it beautiful. In one move he can choose an index i (1≤i<n), delete numbers ai,ai+1 and put numbers ai-ai+1,ai+ai+1 in their place instead, in this order. He wants perform as few operations as possible. Find the minimal number of operations to make sequence A beautiful if it’s possible, or tell him that it is impossible to do so.
is the biggest non-negative number d such that d divides bi for every i (1≤i≤n).

## Input

The first line contains a single integer n (2≤n≤100000) — length of sequence A. The second line contains n space-separated integers a1,a2,...,an (1≤ai≤109) — elements of sequence A.

## Output

Output on the first line "YES" (without quotes) if it is possible to make sequence A beautiful by performing operations described above, and "NO" (without quotes) otherwise. If the answer was "YES", output the minimal number of moves needed to make sequence A beautiful.

## 题解

## AC code:(不包含输入类)