#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  scanf("%lf %lf %lf %lf", &d, &h, &v, &e);
  double a = acos(-1.0) * (d * d) * (1.0 / 4);
  double fill = v / a;
  double ans = fill - e;
  if (ans < 0)
    printf("NO\n");
  else
    printf("YES\n%0.4lf\n", (h / ans));
}
