#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1);
double d, h, v, e, r;
int main() {
  scanf("%lf %lf %lf %lf", &d, &h, &v, &e);
  r = d / 2;
  double vol = pi * (r * r) * h;
  e = e * (pi * (r * r));
  double down = v - e;
  if (down < 0) {
    printf("NO\n");
  } else {
    printf("YES\n");
    double ans = vol / down;
    printf("%.6lf\n", ans);
  }
  return 0;
}
