#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
const float pi = 3.14159265359;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  float d, h, v, e;
  cin >> d >> h >> v >> e;
  float hd = (v * 4) / (pi * d * d);
  if (hd <= e)
    cout << "NO";
  else {
    float time = h / (hd - e);
    cout << "YES" << endl;
    cout << time;
  }
  return 0;
}
