#include <bits/stdc++.h>
using namespace std;
int main() {
  double pi = M_PI;
  int d, h, v, e;
  cin >> d >> h >> v >> e;
  double res = 0;
  if (v > ((pi * d * d * e) / 4)) {
    cout << "YES" << endl;
    res = (-(pi * d * d * h) / 4) / (((pi * d * d * e) / 4) - v);
    cout << res << endl;
  } else {
    cout << "NO" << endl;
  }
  return 0;
}
