#include <bits/stdc++.h>
int main() {
  int d, h, v, e;
  scanf("%d", &d);
  scanf("%d", &h);
  scanf("%d", &v);
  scanf("%d", &e);
  int i, temp;
  float d1, h1, v1, e1;
  d1 = (float)d;
  h1 = (float)h;
  v1 = (float)v;
  e1 = (float)e;
  float hin = (v * 4) / (3.14159265358979323846 * d1 * d1);
  float diff = fabs(hin - e1);
  if ((hin - e1) > 0) {
    float time = (h1 / (hin - e1));
    printf("YES\n");
    printf("%f", time);
  } else {
    printf("NO");
  }
}
