#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e;
  scanf("%d%d%d%d", &d, &h, &v, &e);
  double a = 4.0 * v / (d * d * 3.1415926);
  double b = 1.0 * e;
  if (a <= b)
    printf("NO\n");
  else
    printf("YES\n%.6llf\n", h / (a - b));
}
