#include <bits/stdc++.h>
int main() {
  int d, h, v, e;
  double r;
  while (scanf("%d %d %d %d", &d, &h, &v, &e) != EOF) {
    r = d * 1.0 / 2;
    double de = r * r * acos(-1.0) * e;
    if ((v - de) >= 0) {
      printf("YES\n");
      printf("%.10lf\n", (r * r * h * acos(-1.0) * 1.0) / (v - de));
    } else
      printf("NO\n");
  }
}
