#include <bits/stdc++.h>
int main() {
  int d, h, v, e;
  double time;
  scanf("%d%d%d%d", &d, &h, &v, &e);
  time =
      (double)(3.141592653589793238462643383279502884197169399375 * d * d * h) /
      (4 * v - 3.141592653589793238462643383279502884197169399375 * d * d * e);
  if (time <= 0 || time > 10000)
    printf("NO\n");
  else
    printf("YES\n%lf\n", time);
  return 0;
}
