#include <bits/stdc++.h>
using namespace std;
const int N = 1e3 + 10;
const double PI = acos(-1.0);
int main() {
  double d, h, v, e;
  scanf("%lf%lf%lf%lf", &d, &h, &v, &e);
  double xx = (d / 2.0) * (d / 2.0) * PI;
  xx = v / xx - e;
  if (xx <= 0)
    printf("NO\n");
  else {
    double ans = h / xx;
    printf("YES\n");
    printf("%lf\n", ans);
  }
  return 0;
}
