N=int(1e5)
n=int(input())
a=list(map(int,input().split()))
son=[[0]*2 for _ in range(31*n)]
idx=0
res=0
def insert(x):
    global idx
    p=0
    for i in reversed(range(0,31)):
        u=x>>i&1
        if son[p][u]==0:#没有就创建新节点
            idx+=1
            son[p][u]=idx
        p=son[p][u]

def query(x):
    p=0
    res=0
    for i in reversed(range(31)):
        u=x>>i&1
        if son[p][~u]:#有相反的就去相反的那条路
            p=son[p][~u]
            res+=1<<i
        else:
            p=son[p][u]
    return res

for x in a:
    insert(x)
for x in a:
    res=max(res,query(x))
print(res)