#include <bits/stdc++.h>
using namespace std;
int d, h, v, e;
int main() {
  cin >> d >> h >> v >> e;
  double time, temp;
  temp = (v - (((3.14159265 * d * d) / 4.0) * e));
  if (temp <= 0) {
    cout << "NO";
  } else {
    cout << "YES\n";
    double initial;
    initial = (3.14159265 * d * d * h) / 4.0;
    initial /= temp;
    printf("%0.12f", initial);
  }
  return 0;
}
