#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long double d, h, v, e;
  cin >> d >> h >> v >> e;
  long double r;
  r = d / (long double)2;
  long double con = v / (M_PI * r * r);
  long double eff = con - e;
  long double vol = (M_PI * r * r * h + e - M_PI * r * r);
  long double ans = h / eff;
  if (h == 0)
    cout << "YES" << endl << "0";
  else if (con < e)
    cout << "NO" << endl;
  else
    cout << "YES" << endl << ans;
  return (0);
}
