#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int Q;
int V[32][2];
set<int> S;

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>Q;
	while(Q--) {
		cin>>i;
		if(i==3) {
			int ret=0;
			if(S.empty()) {
				cout<<-1<<endl;
			}
			else {
				FOR(j,30) if(V[j][0]==0&&V[j][1]) ret|=1<<j;
				cout<<ret<<endl;
			}
		}
		else {
			cin>>x;
			if(i==1) {
				if(S.count(x)) continue;
				S.insert(x);
				FOR(j,30) V[j][(x>>j)%2]++;
			}
			else {
				if(S.count(x)==0) continue;
				S.erase(x);
				FOR(j,30) V[j][(x>>j)%2]--;
			}
		}
	}
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}