#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e;
  cin >> d >> h >> v >> e;
  double v1, v2;
  v1 = (v / (M_PI * d * d)) * 4;
  v2 = e;
  if (v1 <= v2) {
    cout << "NO";
    return 0;
  }
  cout << "YES" << endl;
  v1 -= v2;
  printf("%.12lf", h / v1);
  return 0;
}
