#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e, r;
  cin >> d >> h >> v >> e;
  r = d / 2;
  double m = acos(-1) * r * r;
  m = v / m;
  m = m - e;
  if (m > 0) {
    m = h / m;
    puts("YES");
    cout << fixed << setprecision(10) << m << endl;
  } else
    puts("NO");
  return 0;
}
