#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T bigmod(T p, T e, T M) {
  long long ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % M;
    p = (p * p) % M;
  }
  return (T)ret;
}
template <class T>
inline T gcd(T a, T b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
template <class T>
inline T modinverse(T a, T M) {
  return bigmod(a, M - 2, M);
}
template <class T>
inline T bpow(T p, T e) {
  long long ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p);
    p = (p * p);
  }
  return (T)ret;
}
struct zz {
  int el1, el2;
  zz() {}
  zz(int a, int c) { el1 = a, el2 = c; }
  bool friend operator<(zz a, zz b) { return a.el1 > b.el1; }
};
int main() {
  int n, m;
  int t, tc = 1;
  int cnt = 0;
  long long N, M, K;
  double d, h, v, e;
  scanf("%lf %lf", &d, &h);
  scanf("%lf %lf", &v, &e);
  double r = d / 2.0;
  double p = (2.0 * acos(0.0)) * r * r * h;
  double x = (2.0 * acos(0.0)) * r * r * e;
  if (x >= v) {
    printf("NO\n");
    return 0;
  }
  double y = v - x;
  double res = p / y;
  printf("YES\n");
  printf("%lf\n", res);
  return 0;
}
