#include <bits/stdc++.h>
using namespace std;
int main() {
  const double PI = 2 * acos(0.0);
  double r, lvl, v, e;
  cin >> r >> lvl >> v >> e;
  r /= 2;
  double a = PI * r * r;
  double h = v / a;
  double delta = e - h;
  if (delta >= 0) {
    cout << "NO" << endl;
  } else {
    cout << "YES" << endl;
    cout << lvl / (-1 * delta);
  }
  return 0;
}
