#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 10;
int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
int n, a[maxn], ans, ci = 0;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    ci = gcd(ci, a[i]);
  }
  if (ci > 1) {
    cout << "YES" << endl << 0;
    return 0;
  }
  for (int i = 1; i <= n; i++) {
    if (a[i] % 2 == 1) {
      if (a[i + 1] % 2 == 1)
        ans++;
      else
        ans += 2;
      i++;
    }
  }
  cout << "YES" << endl;
  cout << ans;
}
