#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double area = pi * d * d / 4.0;
  double u = e * area;
  double m = h * area;
  double g = v - u;
  if (g <= 1e-10) {
    printf("NO\n");
  } else {
    double ans = m / g;
    printf("YES\n");
    printf("%.6lf\n", ans);
  }
}
