#include <bits/stdc++.h>
using namespace std;
const double PI = 3.141592654589;
int main(int argc, char const *argv[]) {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double drink_speed = v / (PI * pow(d / 2, 2)), delta = drink_speed - e;
  if (delta <= 0)
    cout << "NO" << endl;
  else {
    double tm = h / delta;
    if (tm >= 10e4)
      cout << "NO" << endl;
    else
      cout << "YES" << endl << tm << endl;
  }
  return 0;
}
