#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double ans = 3.14159265359 * d * d * h / (4 * v - 3.14159265359 * d * d * e);
  if (ans < 0)
    cout << "NO"
         << "\n";
  else {
    cout.precision(17);
    cout << "YES"
         << "\n"
         << ans << "\n";
  }
}
