#include <bits/stdc++.h>
using namespace std;
int main() {
  long long d, h, v, e;
  cin >> d >> h >> v >> e;
  double w = (4.0 * v / acos(-1) * d * d) - e;
  if (4.0 * v <= e * d * d * acos(-1))
    cout << "NO\n";
  else {
    double ans = acos(-1) * d * d * h / (4.0 * v - e * acos(-1) * d * d);
    printf("YES\n%.12lf\n", ans);
  }
}
