from collections import defaultdict
d = defaultdict(int)
q = int(input())
l = [0] *30
cnt = 0
for _ in range(q):
    qr = list(input().split())
    if qr[0] == "1":
        x = int(qr[1])
        if d[x] == 0:
            d[x] = 1
            cnt += 1
            i = 0
            while x:
                if x & 1:l[i] += 1
                x >>= 1
                i += 1
    elif qr[0] == "2":
        x = int(qr[1])
        if d[x] :
            d[x] = 0
            cnt -= 1
            i = 0
            while x:
                if x & 1:l[i] -= 1
                x >>= 1
                i += 1
    else:
        if cnt == 0:print(-1)
        else:
            ans = 0
            for i in range(30):
                if l[i] == cnt:
                    ans += 2 ** i
            print(ans)