S = set()
B = [0 for i in range(31)]
q = int(input())
for i in range(q):
    L = list(map(int, input().split()))
    if L[0] == 1:
        if not (a := L[1]) in S:
            S.add(a)
            cnt = 0
            while a:
                B[cnt] += a % 2
                a //= 2
                cnt += 1

    elif L[0] == 2:
        if (a := L[1]) in S:
            S.discard(a)
            cnt = 0
            while a:
                B[cnt] -= a % 2
                a //= 2
                cnt += 1
    else:
        ret = 0
        for i in range(len(B)):
            if B[i] == len(S):
                ret += 2**i
        #        print("#", end=" ")
        print(ret if S else -1)