N = int(input())
A = list(map(int, input().split())) 
B = []
for a in A:
    B.append(format(a, 'b')[::-1])
i = 0
while True:
    all0 = True
    for b in B:
        if len(b)>i and b[i]=='1':
            all0=False
    if all0:
        break
    i+=1
print(2**i)