#include <bits/stdc++.h>
using namespace std;
int d, h, v, e;
const float PI = 3.14159265359;
void solve() {
  cout << fixed << setprecision(4);
  cin >> d >> h >> v >> e;
  float dec = 4 * v / (d * d * PI);
  if (dec <= e) {
    cout << "NO";
    return;
  }
  cout << "YES"
       << "\n";
  cout << (double)h * d * d * PI / (4 * v - (double)e * d * d * PI);
}
int main() {
  solve();
  return 0;
}
