q = int(input())
xor = 0
s = set()

bit = [0]*30
for _ in range(q):
    l = list(map(int,input().split()))
    if l[0] == 1:
        x = l[1]
        if x in s:
            continue
        s.add(x)
        for i in range(30):
            if x >> i & 1:
                bit[i] += 1
    elif l[0] == 2:
        x = l[1]
        if x in s:
            s.remove(x)
            for i in range(30):
                if x >> i & 1:
                    bit[i] -= 1
    else:

        bitwise = 0
        le = len(s)
        for i in range(30):
            if bit[i] == le:
                bitwise += 1 << i
        if le == 0:
            bitwise = -1
        print(bitwise)