#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  while (cin >> d >> h >> v >> e) {
    double s = d / 2;
    s = s * s * 3.1415926535;
    double p1 = v / s;
    if (p1 > e)
      cout << "YES\n";
    else {
      cout << "NO\n";
      continue;
    }
    double p = p1 - e;
    printf("%.12f\n", h / p);
  }
  return 0;
}
