#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e;
  double v1, v2, num, ans;
  scanf("%d%d%d%d", &d, &h, &v, &e);
  v1 = (double)v * 4;
  v2 = (double)d * d * e * acos(-1);
  if (v1 <= v2) {
    printf("NO\n");
  } else {
    printf("YES\n");
    num = (double)d * d * h * acos(-1);
    ans = num / (v1 - v2);
    printf("%.12lf\n", ans);
  }
  return 0;
}
