#include <bits/stdc++.h>
int main() {
  int d, h, v, e;
  scanf("%d%d%d%d", &d, &h, &v, &e);
  double r = d / 2.0;
  if (e > v / (M_PI * r * r)) {
    printf("NO\n");
  } else {
    printf("YES\n");
    printf("%f\n", h / (v / (M_PI * r * r) - e));
  }
  return 0;
}
