#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, e;
  float t, v, r;
  cin >> r >> h >> v >> e;
  r /= 2;
  v = v / (acos(-1) * r * r);
  if (v - e > 0) {
    t = h / (v - e);
    cout << "YES\n" << t;
  } else
    cout << "NO";
  return 0;
}
