#include <bits/stdc++.h>
int main(void) {
  double d, h, v, e;
  scanf("%lf %lf %lf %lf", &d, &h, &v, &e);
  double r = (v / ((d / 2) * (d / 2) * 3.14159265359)) - e;
  if (r < 0)
    printf("NO\n");
  else
    printf("YES\n%.5lf\n", h / r);
  return 0;
}
