import sys
readline = sys.stdin.readline

Q = int(readline())
S = set()
M = 35
D = [0] * M
cnt = 0
for _ in range(Q):
    query = list(map(int, readline().split()))
    if query[0] == 1:
        x = query[1]
        if x in S:
            continue
        S.add(x)
        cnt += 1
        for i in range(M):
            if (x >> i) & 1:
                D[i] += 1
    elif query[0] == 2:
        x = query[1]
        if x in S:
            S.discard(query[1])
            cnt -= 1
            for i in range(M):
                if (x >> i) & 1:
                    D[i] -= 1
    else:
        v = 0
        if cnt == 0:
            print(-1)
            continue
        for i in range(M):
            if D[i] == cnt:
                v += 1 << i
        print(v)