#include <bits/stdc++.h>
int main() {
  int i, j;
  int d, h, v, e;
  scanf("%d %d %d %d", &d, &h, &v, &e);
  double inc = (v * 4) / (d * d * 3.14159265359);
  if (inc <= e) {
    printf("NO\n");
    return 0;
  }
  printf("YES\n");
  double ans = h / (inc - e);
  printf("%f", ans);
  return 0;
}
