#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, c;
  double init, k, t;
  scanf("%d %d %d %d", &d, &h, &v, &c);
  init = (double)h * 3.1415926535898 * (double)d * (double)d / 4.0;
  k = -(double)v + ((double)c * 3.1415926535898 * (double)d * (double)d / 4.0);
  t = -init / k;
  if (t >= 0) {
    printf("YES\n%.12lf\n", t);
  } else {
    printf("NO\n");
  }
  return 0;
}
