#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
int n, a[maxn], ans;
int gcd(int x, int y) {
  if (y == 0) return x;
  return gcd(y, x % y);
}
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  int x = gcd(a[1], a[2]);
  for (int i = 3; i <= n; i++)
    if (x > 1) {
      x = gcd(x, a[i]);
    }
  if (x > 1) {
    cout << "YES" << endl;
    cout << "0" << endl;
  } else {
    for (int i = 1; i < n; i++) {
      if (a[i] % 2 == 0)
        continue;
      else if (a[i + 1] % 2 == 0)
        ans += 2, a[i] = 0;
      else
        ans++, a[i + 1] = 0, a[i] = 0;
    }
    if (a[n] % 2 == 0) {
      cout << "YES" << endl;
      cout << ans << endl;
    } else {
      cout << "YES" << endl;
      cout << ans + 2 << endl;
    }
  }
}
