#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double decrease = v / ((d / 2) * (d / 2) * acos(-1));
  double add = e;
  if (decrease > add) {
    cout << "YES" << endl;
    printf("%.12f\n", h / (decrease - add));
  } else {
    cout << "NO" << endl;
  }
  return 0;
}
