#include <bits/stdc++.h>
using namespace std;
double pi = 3.1415926535;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  if ((4 * v) / (pi * d * d) < e) {
    cout << "NO\n";
    return 0;
  }
  cout << "YES\n";
  cout << h / ((4 * v) / (pi * d * d) - e) << "\n";
  return 0;
}
