#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
const long long INF = 1e18 + 1LL;
const double Pi = acos(-1.0);
const int N = 1e6 + 10, M = 1e3 + 20, mod = 1e9 + 7, inf = 2e9;
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
int a[N], b[N], n;
set<long long> s;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) scanf("%d", &a[i]);
  long long G = gcd(a[1], a[2]);
  for (int i = 2; i <= n; ++i) {
    G = gcd(G, a[i]);
  }
  if (G != 1) {
    puts("YES");
    cout << 0 << endl;
    return 0;
  }
  puts("YES");
  int ans = 0;
  for (int i = 1; i <= n; i += 1) {
    if (a[i] % 2 == 1 && a[i + 1] % 2 == 0)
      ans += 2, a[i] = 0;
    else if (a[i] % 2 == 1 && a[i + 1] % 2 == 1)
      ans++, a[i + 1] = 0;
  }
  cout << ans << endl;
  return 0;
}
