#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
int main() {
  double d, h, v, e;
  while (scanf("%lf%lf%lf%lf", &d, &h, &v, &e) != EOF) {
    double t = v / (PI * (d / 2) * (d / 2));
    if (t > e) {
      printf("YES\n");
      double ti = h / (t - e);
      printf("%lf\n", ti);
    } else
      printf("NO\n");
  }
  return 0;
}
