#include <stdio.h>
#include <algorithm>
#include <vector>
using namespace std;

int N, K, A[2020];

int main()
{
	scanf ("%d %d", &N, &K);
	for (int i = 0; i < N; i++) scanf ("%d", &A[i]);
	sort(A, A + N);

	vector<int> cand = { K };
	int x = 0;
	for (int i = N - 1; i >= 0; i--){
		int k = cand.size();
		for (int j = 0; j < k; j++){
			cand.push_back(cand[j] % A[i]);
			if (i == 0) x = max(x, cand.back());
		}
		sort(cand.begin(), cand.end());
		cand.erase(unique(cand.begin(), cand.end()), cand.end());
	}

	printf ("%d\n", x);

	return 0;
}