#include <bits/stdc++.h>
using namespace std;
double d, h, v, e;
int main() {
  ios_base::sync_with_stdio(false);
  cin >> d >> h >> v >> e;
  v = v / (acos(-1) * d * d / 4);
  double t = h / (v - e);
  if (t < 0 || fabs(v - e) < 1e-8) {
    printf("NO\n");
    return 0;
  }
  printf("YES\n%.12lf\n", t);
  return 0;
}
