#include <bits/stdc++.h>
using namespace std;
void nandini() {
  double d, h, v, e, x, y;
  cin >> d >> h >> v >> e;
  double a = ((4 * v) / (3.1415926535897 * d * d));
  if (a <= e)
    cout << "NO";
  else {
    cout << "YES" << endl;
    std::cout << std::setprecision(9) << (h / (a - e));
  }
  cout << endl;
  return;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int t = 1;
  while (t--) {
    nandini();
  }
  return 0;
}
