#include <bits/stdc++.h>
using namespace std;
double d, h, v, e, pi = 3.1415926535, t;
int main() {
  cin >> d >> h >> v >> e;
  if (e >= (v / (pi * d * d / 4))) {
    cout << "NO";
    return 0;
  } else {
    t = h / (v / (pi * d * d / 4) - e);
  }
  cout << "YES" << endl << t;
  return 0;
}
