#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e;
  cin >> d >> h >> v >> e;
  float r = (float)d / 2;
  float initialVol = 3.141592654 * pow(r, 2) * h;
  float incVol = 3.141592654 * pow(r, 2) * e;
  if (v <= incVol)
    cout << "NO";
  else
    cout << "YES" << endl << (initialVol / (v - incVol));
  return 0;
}
