#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e, sum;
  scanf("%lf %lf %lf %lf", &d, &h, &v, &e);
  if (v < (d / 2) * (d / 2) * 3.1415926 * e)
    printf("NO\n");
  else {
    printf("YES\n");
    sum = (3.1415926 * (d / 2) * (d / 2) * h) /
          (v - (3.1415926 * (d / 2) * (d / 2) * e));
    printf("%.12lf\n", sum);
  }
  return 0;
}
