#include <bits/stdc++.h>
using namespace std;
double val, d, h, e, v, r;
double pie = 3.14159265358979;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> d >> h >> v >> e;
  r = d / 2.000;
  val = v - pie * r * r * e;
  if (val < 0)
    cout << "NO";
  else {
    cout << "YES\n";
    val = (pie * r * r * h) / val;
    cout << fixed;
    cout << setprecision(15);
    cout << val;
  }
  return 0;
}
