#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;

bool Mbe;
constexpr int N = 1e7 + 5;

int n, k;
vector<int> d;
double f[N];
void solve() {
  cin >> n >> k;
  if(k == 1) cout << "1\n", exit(0);
  for(int l = 1; l <= k; ) {
    int c = (k - 1) / l + 1;
    d.push_back(c);
    if(c > 1) l = (k - 1) / (c - 1) + 1;
    else l = k + 1;
  }
  f[k] = 1;
  for(int i = 1, a; i <= n; i++) {
    cin >> a;
    for(int j = d.size() - 2; ~j; j--) {
      for(int l = 2; l <= d[j]; ) {
        int c = (d[j] - 1) / l + 1;
        f[c] = max(f[c], f[d[j]] * (a / l) / a);
        if(c > 1) l = (d[j] - 1) / (c - 1) + 1;
        else l = d[j] + 1;
      }
    }
  }
  printf("%.12lf\n", f[1] * k);
}

bool Med;
int main() {
  fprintf(stderr, "%.3lf MB\n", (&Mbe - &Med) / 1048576.0);
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int T = 1;
  while(T--) solve();
  cerr << 1e3 * clock() / CLOCKS_PER_SEC << " ms\n";
  return 0;
}