#include <bits/stdc++.h>
using namespace std;
 
#define fi first
#define se second
#define pb push_back
using vi = vector <int>;
using ll = long long;
using pii = pair <int, int>;
//~ const ll mod = 998244353;
const ll mod = 1e9 + 7;
ll qpow(ll a, ll b, ll m = mod) { ll r = 1, t = a;
	for(; b; b /= 2) { if(b & 1) r = r * t % m; t = t * t % m; } return r; }

int cb[31];

int main() {
	ios :: sync_with_stdio(false);
	
	int q; cin >> q;
	set <int> st;
	while(q --) {
		int t; cin >> t;
		if(t == 3) {
			if(st.size() == 0)
				cout << "-1\n";
			else {
				int ans = 0;
				for(int i = 0; i <= 30; i ++)
					if(cb[i] == st.size())
						ans |= (1 << i);
				cout << ans << '\n';
			}
		} else {
			int x; cin >> x;
			
			if(t == 1) {
				if(st.count(x)) continue;
				else st.insert(x);
			} else {
				if(!st.count(x)) continue;
				st.erase(x);
			}
			
			int sgn = (t == 1 ? 1 : -1);
			for(int i = 0; i <= 30; i ++)
				if((x >> i) & 1)
					cb[i] += sgn;
		}
	}
}