#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e;
  cin >> d >> h >> v >> e;
  long double area = 0.0, vol = 0.0;
  long double pi =
      3.141592653589793238462643383279502884197169399375105820974944592307816406286;
  area = (pi * d * d * 1.0) / 4;
  vol = area * h * 1.0;
  if (e > v)
    cout << "NO\n";
  else {
    if (v > e * area) {
      cout << "YES\n";
      long double ans = (vol * 1.0) / (v - e * area);
      cout << ans << endl;
    } else {
      cout << "NO\n";
    }
  }
  return 0;
}
