#include <bits/stdc++.h>
int main() {
  int d, h, v, e;
  scanf("%d%d%d%d", &d, &h, &v, &e);
  double r = d * 1.0 / 2;
  if (acos(-1) * r * r * e - v >= 0) {
    printf("NO\n");
  } else {
    double t = acos(-1) * r * r * h / (v - acos(-1) * r * r * e);
    printf("YES\n");
    printf("%0.12lf\n", t);
  }
}
