n = int(input())
A = list(map(int, input().split()))

B = [[0 for _ in range(61)] for _ in range(n)]
for i in range(n):
    Ac = A[i]
    for j in range(61):
        B[i][j] = Ac % 2
        Ac //= 2
for i in range(61):
    flag = True
    for j in range(n):
        if B[j][i] == 1:
            flag = False
            break
    if flag:
        print(pow(2, i))
        break