bit=[0 for _ in range(30)]

q=int(input())

S=set()
for _ in range(q):
    A=list(map(int,input().split()))
    if A[0]==1:
        x=A[1]
        if x in S:
            continue
        S.add(x)
        cnt=0
        while(x>0):
            bit[cnt]+=x%2
            x//=2
            cnt+=1

    if A[0]==2:
        x=A[1]
        if x not in S:
            continue
        S.remove(x)
        cnt=0
        while(x>0):
            bit[cnt]-=x%2
            x//=2
            cnt+=1
    if A[0]==3:
        L=len(S)
        if L==0:
            print(-1)
            continue
        cnt=0
        b_and=0
        for i in range(30):
            if bit[i]==L:
                b_and+=2**i
        print(b_and)