Q = int(input())

s = set()
num = 0
C = 30
dat = [0] * C

for _ in range(Q):
    l = list(map(int,input().split()))
    if l[0] == 1:
        x = l[1]
        if x not in s:
            s.add(x)
            num += 1
            for i in range(C):
                mask = 1 << i
                if x & mask:
                    dat[i] += 1
    elif l[0] == 2:
        x = l[1]
        if x in s:
            num -= 1
            s.remove(x)
            for i in range(C):
                mask = 1 << i
                if x & mask:
                    dat[i] -= 1
    else:
        if num == 0:
            print(-1)
            continue
        ans = 0
        for i in range(C):
            mask = 1 << i
            if dat[i] == num:
                ans |= mask
        print(ans)