686

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

using namespace __gnu_pbds;
using namespace std;

const int MOD = 1000000000;

typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;

int main() {
    set <int> s;
    int q, x, tmpa = 0;
    char type, tmpc = '+';
    cin >> q;
    while (q --) {
        cin >> type >> x;
        if (type == '+') {
            if (tmpc == '+')
                s.insert (x);
            else
                s.insert ((x + tmpa) % MOD);
        } else {
            set <int> :: iterator it = s.lower_bound (x);
            if (*it == x) {
                tmpa = x;
                cout << tmpa << endl;
                continue;
            }
            if (it == s.end())
                tmpa = -1, cout << tmpa << endl;
            else
                tmpa = *(it), cout << tmpa << endl;
        }
        tmpc = type;
    }
    return 0;
}