import sys read=sys.stdin.buffer.read;readline=sys.stdin.buffer.readline;input=lambda:sys.stdin.readline().rstrip() import bisect,string,math,time,functools,random,fractions from bisect import* from heapq import heappush,heappop,heapify from collections import deque,defaultdict,Counter from itertools import permutations,combinations,groupby import itertools rep=range;R=range def I():return int(input()) def LI():return [int(i) for i in input().split()] def SLI():return sorted([int(i) for i in input().split()]) def LI_():return [int(i)-1 for i in input().split()] def S_():return input() def IS():return input().split() def LS():return [i for i in input().split()] def NI(n):return [int(input()) for i in range(n)] def NI_(n):return [int(input())-1 for i in range(n)] def NLI(n):return [[int(i) for i in input().split()] for i in range(n)] def NLI_(n):return [[int(i)-1 for i in input().split()] for i in range(n)] def StoLI():return [ord(i)-97 for i in input()] def ItoS(n):return chr(n+97) def LtoS(ls):return ''.join([chr(i+97) for i in ls]) def RLI(n=8,a=1,b=10):return [random.randint(a,b)for i in range(n)] def RI(a=1,b=10):return random.randint(a,b) def GI(V,E,ls=None,Directed=False,index=1): org_inp=[];g=[[] for i in range(V)] FromStdin=True if ls==None else False for i in range(E): if FromStdin: inp=LI() org_inp.append(inp) else: inp=ls[i] if len(inp)==2:a,b=inp;c=1 else:a,b,c=inp if index==1:a-=1;b-=1 aa=a,c,;bb=b,c,;g[a].append(bb) if not Directed:g[b].append(aa) return g,org_inp def RE(E): rt=[[]for i in range(len(E))] for i in range(len(E)): for nb,d in E[i]: rt[nb]+=(i,d), return rt def RLE(it): rt=[] for i in it: if rt and rt[-1][0]==i:rt[-1][1]+=1 else:rt+=[i,1], return rt def GGI(h,w,search=None,replacement_of_found='.',mp_def={'#':1,'.':0},boundary=1): #h,w,g,sg=GGI(h,w,search=['S','G'],replacement_of_found='.',mp_def={'#':1,'.':0},boundary=1) # sample usage mp=[boundary]*(w+2);found={} for i in R(h): s=input() for char in search: if char in s: found[char]=((i+1)*(w+2)+s.index(char)+1) mp_def[char]=mp_def[replacement_of_found] mp+=[boundary]+[mp_def[j] for j in s]+[boundary] mp+=[boundary]*(w+2) return h+2,w+2,mp,found def TI(n):return GI(n,n-1) def accum(ls): rt=[0] for i in ls:rt+=[rt[-1]+i] return rt def bit_combination(n,base=2): rt=[] for tb in R(base**n):s=[tb//(base**bt)%base for bt in R(n)];rt+=[s] return rt def gcd(x,y): if y==0:return x if x%y==0:return y while x%y!=0:x,y=y,x%y return y def YN(x):print(['NO','YES'][x]) def Yn(x):print(['No','Yes'][x]) def show(*inp,end='\n'): if show_flg:print(*inp,end=end) inf=float('inf') FourNb=[(-1,0),(1,0),(0,1),(0,-1)];EightNb=[(-1,0),(1,0),(0,1),(0,-1),(1,1),(-1,-1),(1,-1),(-1,1)];compas=dict(zip('WENS',FourNb));cursol=dict(zip('UDRL',FourNb));HexNb=[(-1,0),(-1,-1),(0,1),(0,-1),(1,1),(1,0)] alp=[chr(ord('a')+i)for i in range(26)] #sys.setrecursionlimit(10**7) def gcj(t,*a): print('Case #{}:'.format(t+1),*a) def INP(): N=80 n=random.randint(1,N) x=random.randint(1,N) return n,x def Rtest(T): case,err=0,0 for i in range(T): inp=INP() #show(inp) a1=naive(*inp) a2=solve(*inp) if a1!=a2: print(inp) n,x=inp a,b=bin(n)[2:],bin(x)[2:] show(a,b) print('naive',a1) print('solve',a2) err+=1 case+=1 print('Tested',case,'case with',err,'errors') mo=998244353 #mo=10**9+7 show_flg=False show_flg=True ans=0 q=I() s=set() D=32 b=[0]*D for i in range(q): t,*x=LI() if t==1: x=x[0] if x not in s: s.add(x) for i in range(D): if x>>i&1: b[i]+=1 elif t==2: x=x[0] if x in s: s.remove(x) for i in range(D): if x>>i&1: b[i]-=1 else: a=0 if s: for i in range(D): if b[i]==len(s): a+=i<<1 else: a=-1 print(a)