#include <bits/stdc++.h>
const double r = 3.141592654;
int main() {
  int d, h, e, v;
  scanf("%d %d %d %d", &d, &h, &v, &e);
  double tang = (double)(4 * v / (d * d * r));
  if (tang <= e)
    printf("NO");
  else {
    printf("YES\n");
    double kq = (double)(h / (tang - e));
    printf("%llf", kq);
  }
}
