#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e;
  double ans;
  cin >> d >> h >> v >> e;
  ans = (3.14159265359 * d * d * h) / ((4 * v) - (3.14159265359 * d * d * e));
  if (ans < 0)
    cout << "NO" << endl;
  else {
    cout << "YES" << endl;
    cout << setprecision(12) << fixed << ans << endl;
  }
  return 0;
}
