Q = int(input())
B = 32

ans = [0] * B
dic = dict()
cnt = 0

for _ in range(Q):
    q = list(map(int, input().split()))
    if q[0] == 1:
        if q[1] not in dic:
            dic[q[1]] = 0
        if dic[q[1]] == 0:
            dic[q[1]] = 1
            for i in range(B):
                if (q[1] >> i) & 1:
                    ans[i] += 1
            cnt += 1
    elif q[0] == 2:
        if q[1] not in dic:
            dic[q[1]] = 0
        if dic[q[1]] == 1:
            dic[q[1]] = 0
            for i in range(B):
                if (q[1] >> i) & 1:
                    ans[i] -= 1
            cnt -= 1
    else:
        a = 0
        for i in range(B - 1, -1, -1):
            a *= 2
            if ans[i] == cnt:
                a += 1
        if cnt == 0:
            print(-1)
        else:
            print(a)