#include <bits/stdc++.h>
using namespace std;
int n;
vector<int> v;
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
int main() {
  scanf("%d", &n);
  long long g = 0;
  for (int i = int(0); i < (int)n; ++i) {
    int a;
    scanf("%d", &a);
    v.push_back(a);
    g = gcd(g, a);
  }
  if (g > 1) {
    printf("YES\n%d\n", 0);
    return 0;
  }
  int ans = 0;
  for (int i = int(0); i < (int)n - 1; ++i) {
    int a, b;
    while (v[i] & 1) {
      a = v[i], b = v[i + 1];
      v[i] = a + b;
      v[i + 1] = a - b;
      ans++;
    }
  }
  int a, b;
  while (v[n - 1] & 1) {
    a = v[n - 2], b = v[n - 1];
    v[n - 2] = a + b;
    v[n - 1] = a - b;
    ans++;
  }
  printf("YES\n%d\n", ans);
  return 0;
}
