#include <bits/stdc++.h>
using namespace std;
const double pi = 3.141592653;
int main() {
  int d, h, v, e;
  while (cin >> d >> h >> v >> e) {
    double v1, v2;
    double r = (double)d / 2;
    v1 = pi * r * r * h;
    v2 = pi * r * r * e;
    if (v <= v2)
      printf("NO\n");
    else {
      double d = (double)v - v2;
      printf("YES\n");
      printf("%.61f\n", v1 / d);
    }
  }
  return 0;
}
