N, K = map(int, input().split())
A = list(map(int, input().split()))
A.sort(reverse=True)
ans = 0


def dfs(X, i):
    if i == N - 1:
        global ans
        ans = max(ans, X % A[i])
        return
    dfs(X, i + 1)
    dfs(X % A[i], i + 1)
    return


dfs(K, 0)
print(ans)