import sys
#sys.setrecursionlimit(10 ** 6)
INF = float('inf')
#10**20,2**63に変えるのもあり
MOD = 10**9 + 7
MOD2 = 998244353
from collections import defaultdict
def solve():
    def II(): return int(sys.stdin.readline())
    def LI(): return list(map(int, sys.stdin.readline().split()))
    def LC(): return list(input())
    def IC(): return [int(c) for c in input()]
    def MI(): return map(int, sys.stdin.readline().split())
    N = II()
    A = LI()
    OR = 0
    for a in A:
        OR = OR|a
    Bit = list(bin(OR)[2:])
    Bit.reverse()
    for i,b in enumerate(Bit):
        if b == "0":
            print(2**i)
            exit()
    print(2**(i+1))
    return
solve()