#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  d /= 2;
  double vol = d * d * acos(-1) * h;
  double incre = e * d * d * acos(-1);
  if (incre >= v) {
    cout << "NO";
    return 0;
  }
  double ans = vol / (v - incre);
  if (ans > 1e4) {
    cout << "NO";
    return 0;
  }
  cout << "YES\n";
  cout << setprecision(15) << ans;
}
