#include <iostream>
#include <stack>
#include <utility>
#include <vector>

using namespace std;

int main()
{
    stack<int> stos;
    vector<stack<int>> dane;
    unsigned n;
    cin >> n;
    pair<char, int> tablica[n];
    for(unsigned i = 0; i < n; ++i)
    {
        cin >> tablica[i].first;
        if(tablica[i].first == '-')
            continue;
        cin >> tablica[i].second;
    }

    // pierwsza operacja:
    stos.push(tablica[0].second);
    dane.push_back(stos);

    // kolejne operacje:
    for(unsigned i = 1; i < n; ++i)
    {
        switch(tablica[i].first)
        {
        case '+':
            stos = dane[i - 1];
            stos.push(tablica[i].second);
            break;
        case '-':
            stos = dane[i - 1];
            stos.pop();
            break;
        case '*':
            stos = dane[i - tablica[i].second - 1];
        }
        dane.push_back(stos);
    }

    for(unsigned i = 0; i < n; ++i)
    {
        if(dane[i].size() == 0)
            cout << -1 << endl;
        else
            cout << dane[i].top() << endl;
    }
    return 0;
}