#include <bits/stdc++.h>
using namespace std;
int n;
int num[100000 + 10];
int gcd(int a, int b) { return (b == 0) ? a : gcd(b, a % b); }
int ans = 0;
int main() {
  int cnt = 0, a, b;
  cin >> n;
  int p, q;
  for (int i = 0; i < n; i++) {
    cin >> num[i];
    if (ans == 0) ans = num[i];
    ans = gcd(ans, num[i]);
  }
  if (ans > 1) {
    cout << "YES" << endl << cnt << endl;
    return 0;
  }
  for (int i = 0; i < n; i++) {
    if (num[i] % 2 == 1 && num[i + 1] % 2 == 1) {
      cnt++;
      num[i] = num[i + 1] = 2;
    }
  }
  for (int i = 0; i < n; i++) {
    if (num[i] % 2 == 1) cnt += 2;
  }
  cout << "YES" << endl << cnt;
  return 0;
}
