#include <bits/stdc++.h>
using namespace std;
int main() {
  float d, h, v, e;
  cin >> d >> h >> v >> e;
  float pi = 3.141592653589793238;
  float area = pi * d * d / 4;
  float fill = area * e;
  float dec_hei = v / area;
  if (fill > v)
    cout << "NO";
  else
    cout << "YES" << endl << h / (dec_hei - e);
}
