#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  double d, h, v, e, r, area, init_vol, growth_vol;
  cin >> d >> h >> v >> e;
  r = (d / 2);
  area = acos(-1.0) * r * r;
  init_vol = area * h;
  growth_vol = area * e;
  if (v < growth_vol)
    cout << "NO" << endl;
  else
    cout << "YES" << endl << (init_vol / (v - growth_vol)) << endl;
  return 0;
}
