Mike and gcd problem

2000ms

262144K

Description:

Mike has a sequence A = [a₁, a₂, ..., a_n] of length n. He considers the sequence B = [b₁, b₂, ..., b_n] beautiful if the gcd of all its elements is bigger than 1, i.e. $\text{[math]}$ .

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 a_i, a_i + 1 and put numbers a_i - a_i + 1, a_i + a_i + 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.

$\text{[math]}$ is the biggest non-negative number d such that d divides b_i for every i (1 ≤ i ≤ n).

Input:

The first line contains a single integer n (2 ≤ n ≤ 100 000) — length of sequence A.

The second line contains n space-separated integers a₁, a₂, ..., a_n (1 ≤ a_i ≤ 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.

Sample Input:

2
1 1

Sample Output:

YES
1

Sample Input:

3
6 2 4

Sample Output:

YES
0

Sample Input:

2
1 3

Sample Output:

YES
1

Note:

In the first example you can simply make one move to obtain sequence [0, 2] with $\text{[math]}$ .

In the second example the gcd of the sequence is already greater than 1.

Informação

Provedor Codeforces

Código CF798C