#include <bits/stdc++.h>
using namespace std;
int a[100010];
int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
int main() {
  int n;
  while (cin >> n) {
    for (int i = 1; i <= n; i++) cin >> a[i];
    int x = a[1];
    for (int i = 2; i <= n; i++) x = gcd(x, a[i]);
    if (x > 1) {
      cout << "YES" << endl << "0" << endl;
      continue;
    }
    int sum = 0;
    for (int i = 1; i <= n; i++) {
      if (a[i] % 2 == 1 && a[i + 1] % 2 == 1) {
        int t1 = a[i] - a[i + 1];
        int t2 = a[i] + a[i + 1];
        a[i] = t1;
        a[i + 1] = t2;
        sum += 1;
      }
    }
    for (int i = 1; i <= n; i++)
      if (a[i] % 2 == 1) {
        sum = sum + 2;
      }
    cout << "YES" << endl << sum << endl;
  }
  return 0;
}
