def solve(q, qu):
    s = set()
    X = []
    bit = [0] * 30
    for v in qu:
        t = v[0]
        if t == 1:
            x = v[1]
            if x not in s:
                s.add(x)
                for i in range(30):
                    if 1 & (x >> i):
                        bit[i] += 1
        elif t == 2:
            x = v[1]
            if x in s:
                s.discard(x)
                for i in range(30):
                    if 1 & (x >> i):
                        bit[i] -= 1
        else:
            ans = 0
            if len(s) == 0:
                X.append(-1)
            else:
                for i in range(30):
                    if bit[i] == len(s):
                        ans += 2 ** i 
                X.append(ans)
    return X

q = int(input())

qu = [list(map(int,input().split())) for _ in range(q)]

for v in solve(q, qu):
    print(v)