#include //#include using namespace std; //using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; //using mint = modint998244353; //const int mod = 998244353; //const int INF = 1e9; //const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n-1); i >= 0; --i) #define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define endl "\n" #define P pair template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int q; cin >> q; setst; vectorcnt(30); while (q--) { int t; cin >> t; if (1 == t) { int x; cin >> x; if (st.count(x))continue; st.insert(x); rep(i, 30) { if (1 & (x >> i))cnt[i]++; } } else if (2 == t) { int x; cin >> x; if (!st.count(x))continue; rep(i, 30) { if (1 & (x >> i))cnt[i]--; } st.erase(x); } else { if (st.empty()) { cout << -1 << endl; continue; } int ans = 0; rep(i, 30) { if (st.size() == cnt[i])ans += 1 << i; } cout << ans << endl; } } return 0; }