#include <bits/stdc++.h>
using namespace std;
int main() {
  float d, h, v, e, pi = 3.141593;
  cin >> d >> h >> v >> e;
  if (v / (pi * d * d / 4) < e) {
    cout << "NO";
    return 0;
  }
  cout << "YES" << endl << h / ((v / ((pi / 4) * d * d)) - e);
  return 0;
}
