#include <bits/stdc++.h>
using namespace std;
const double pi = 3.14159265359;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double r = d / 2.0;
  double s = v / (pi * r * r);
  if (s - e <= 0) {
    cout << "NO" << endl;
    return 0;
  }
  double diff = s - e;
  cout << "YES" << endl;
  printf("%.6lf\n", h / diff);
}
