#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)
#define all(x) begin(x), end(x)
template <class T> bool chmin(T& x, T y) {
	return x > y ? (x = y, true) : false;
}
template <class T> bool chmax(T& x, T y) {
	return x < y ? (x = y, true) : false;
}

using mint = atcoder::modint998244353;

void solve() {
	int n, k;
	cin >> n >> k;
	int m = 1e6 + 10;
	vector<int> a(m);
	rep(i, 0, n) {
		int x;
		cin >> x;
		a[x]++;
	}
	rep(i, 1, m) {
		for (int j = i * 2; j < m; j += i) {
			a[i] += a[j];
		}
	}
	int ans = 0;
	rep(i, 0, m) if ((ll)(n - a[i] + 1) * (k - 1) <= a[i]) ans = i;
	cout << ans << '\n';
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(15);
	int t = 1;
	// cin >> t;
	while (t--) solve();
}