#include <bits/stdc++.h>
using namespace std;
int cmpare(int v, int e) {
  return (v - e) > -1e-9;
  return 0;
}
int main() {
  int d, h, v, e;
  scanf("%d %d %d %d", &d, &h, &v, &e);
  double area = (3.1415926535897 * d * d) / 4;
  double vArea = v / area;
  if (cmpare(vArea, e)) {
    double dem = vArea;
    double ans = h / (dem - e);
    if (ans < 1e4) {
      puts("YES");
      printf("%0.12lf\n", ans);
    } else
      puts("NO");
  } else
    puts("NO");
  return 0;
}
