#include <bits/stdc++.h>
using namespace std;
int t;
double pi = acos(-1.0);
double d, h, v, e;
int main() {
  scanf("%lf%lf%lf%lf", &d, &h, &v, &e);
  double r = d / 2;
  if (pi * r * r * e > v)
    cout << "NO" << endl;
  else {
    double s = (pi * r * r * h) / (v - pi * r * r * e);
    cout << "YES" << endl;
    printf("%.12f\n", s);
  }
  return 0;
}
