s = set()
cnt = [0 for i in range(30)]
for _ in range(int(input())):
    alist = list(map(int,input().split()))
    if alist[0] == 1:
        if alist[1] not in s:
            s.add(alist[1])
            for i in range(30):
                cnt[i] += (alist[1] >> i) & 1
    
    if alist[0] == 2:
        if alist[1] in s:
            s.discard(alist[1])
            for i in range(30):
                cnt[i] -= (alist[1] >> i) & 1
    
    if alist[0] == 3:
        ans = 0
        for i in range(30):
            if len(s) == 0:
                ans = -1
                break
            ans += pow(2,i) * (1 if cnt[i] == len(s) else 0)
        print(ans)