# セグメントツリーでできたが前回の方法でもやってみる
# 30桁しかないのでそれぞれの桁に1が何回出たかカウントすればいい

Q = int(input())
one_count = [0]*30
S = set()
count = 0
for q in range(Q):
    query = list(map(int, input().split()))
    if query[0] == 1:
        x = query[1]
        if x not in S:
            S.add(x)
            count += 1
            for i in range(30):
                if x>>i&1 == 1:
                    one_count[i] += 1
    elif query[0] == 2:
        x = query[1]
        if x in S:
            S.discard(x)
            count -= 1
            for i in range(30):
                if x>>i&1 == 1:
                    one_count[i] -= 1
    elif query[0] == 3:
        if count > 0:
            ans = 0
            for d in range(30):
                if one_count[d] == count:
                    ans += pow(2, d)
            print(ans)
        else:
            print(-1)
    #print('q', q, 'count', count)
    #print('one_count', one_count)