//
  // Created by ronal on 2/11/2023.
  // Problem Description Link.
  // https://practice.geeksforgeeks.org/problems/geek-and-books/0
  
  #include <bits/stdc++.h>
  using namespace std;
  
  int main() {
      stack<int> Stak;
      int tests, size, value;
      string type;
  
      cin >> tests;
      for(int i = 0; i < tests; i++){
          cin >> size;
          for(int j = 0; j < size; j++){
              cin >> type;
              if(type.compare("place") == 0){
                  cin >> value;
                  Stak.push(value);
              }else{
                  if(Stak.empty()){
                      cout << "-1 ";
                  }else{
                      cout << Stak.top() << " ";
                      Stak.pop();
                  }
              }
          }
  
          while(!Stak.empty()){
              Stak.pop();
          }
          cout << "
  ";
      }
      return 0;
  }