#include <bits/stdc++.h>
using namespace std;
long long d, h, v, e;
float ans, cnt;
int main() {
  cin >> d >> h >> v >> e;
  ans = (v * 4) / (3.141592653589 * (d * d));
  if (e >= ans)
    cout << "NO";
  else {
    cout << "YES" << endl;
    cnt = h / ((4 * v) / (3.141592653589 * (d * d)) - e);
    cout << fixed << setprecision(12) << cnt;
  }
}
