#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
int main() {
  double d, h, v, e;
  scanf("%lf%lf%lf%lf", &d, &h, &v, &e);
  d /= 2;
  double V = pi * d * d * h;
  double dv = pi * d * d * e;
  if (v <= dv) {
    printf("NO\n");
    return 0;
  } else {
    printf("YES\n");
    printf("%.10f\n", V / (v - dv));
  }
  return 0;
}
