#include <bits/stdc++.h>
using namespace std;
long long int modpow(long long int a, long long int n, long long int temp) {
  long long int res = 1, y = a;
  while (n > 0) {
    if (n & 1) res = (res * y) % temp;
    y = (y * y) % temp;
    n /= 2;
  }
  return res % temp;
}
int main() {
  int d, h, v, e;
  scanf("%d", &d);
  scanf("%d", &h);
  scanf("%d", &v);
  scanf("%d", &e);
  double t = double(e) - double(4 * v) / double(3.1415926 * d * d);
  t = -1.0 * t;
  if (t <= 0) {
    printf("NO\n");
    return 0;
  } else
    t = double(h) / t;
  printf("YES\n");
  printf("%.4lf\n", t);
  return 0;
}
