q = int(input())
joutai = [0 for i in range(31)]
s = {}
ss = {}
for i in range(q):
    a = list(map(int,input().split()))
    if a[0] == 1:
        if a[1] not in s:
            b = []
            x = a[1]
            while x > 1:
                if x % 2 == 0:
                    b.append("0")
                else:
                    b.append("1")
                x //= 2
            b.append("1")
          #  print(b)
            for j in range(len(b)):
                if b[j] == "1":
                    joutai[j] += 1
            s[a[1]] = 1
    elif a[0] == 2:
        if a[1] in s:
            b = []
            x = a[1]
            while x > 1:
                if x % 2 == 0:
                    b.append("0")
                else:
                    b.append("1")
                x //= 2
            b.append("1")
         #   print(b)
            for j in range(len(b)):
                if b[j] == "1":
                    joutai[j] -= 1
            s.pop(a[1])
    else:
        ans = 0
        su = len(s)
        if su == 0:
            print(-1)
            continue
        for i in range(len(joutai)):
            if joutai[i] == su:
                ans += 2**i
        print(ans)
   # print(s,joutai)