import sys
input = sys.stdin.readline

Q=int(input())
S=set()
A=[0]*32
ko=0

for tests in range(Q):
    X=list(map(int,input().split()))

    if X[0]==1:
        x=X[1]

        if x in S:
            pass
        else:
            S.add(x)
            ko+=1

            for i in range(32):
                if x & (1<<i) != 0:
                    A[i]+=1

    elif X[0]==2:
        x=X[1]

        if x in S:
            S.remove(x)
            ko-=1

            for i in range(32):
                if x & (1<<i) != 0:
                    A[i]-=1

    else:
        ANS=-1

        for i in range(32):
            if A[i]>0 and ANS==-1:
                ANS=0
            if A[i]>0 and A[i]==ko:
                ANS|=(1<<i)

        print(ANS)