#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1.0);
int main() {
  int d, h;
  double v, e;
  while (cin >> d >> h >> v >> e) {
    double x = PI * d * d / 4;
    v = v / x;
    v -= e;
    if (v <= 0) {
      puts("NO");
      continue;
    }
    double t = h / v;
    if (t > 10000)
      puts("NO");
    else
      printf("YES\n%.10lf\n", t);
  }
  return 0;
}
