iostream

#include <iostream>
#include <array>
#include <algorithm>
#include <map>
#include <set>

using namespace std;

int main() {
    const long mod = 1e9;
    int n;
    cin >> n;
    set<long> S;
    char c;
    pair<int, long> prev = {0, 0};
    for (int i = 0; i < n; ++i){
        cin >> c;
        if (c == '+'){
            long x;
            cin >> x;
            if (prev.first){
                S.insert((x + prev.second) % mod);
            }
            else {
                S.insert(x);
            }
            prev.first = 0;
            continue;
        }
        if (c == '?'){
            long x;
            cin >> x;
            auto it1 = S.find(x);
            prev.first = 1;
            if (it1 != S.end()){
                cout << x << endl;
                prev.second = x;
            }
            else {
                auto it2 = S.upper_bound(x);
                if (it2 != S.end()){
                    cout << *it2 << endl;
                    prev.second = *it2;
                }
                else {
                    cout << -1 << endl;
                    prev.second = -1;
                }
            }
            continue;

        }
    }
}