#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double total = (acos(-1.0) * (d / 2.0) * (d / 2.0)) * h;
  total = total / 1000.00;
  e = (acos(-1.0) * (d / 2.0) * (d / 2.0)) * e;
  double diff = v - e;
  if (diff <= 0) {
    cout << "NO\n";
  } else {
    cout << "YES\n";
    cout << (total / diff) * 1000 << '\n';
  }
  return 0;
}
