N, K = map(int, input().split())
A = list(map(int, input().split()))
A.sort()
ans = 0
def dfs(k, x):
    global ans
    if x == 0:
        ans = max(ans, k % A[0])
        return
    for i in range(x):
        dfs(k % A[i], i)

dfs(K, N)
print(ans)