#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using Graph=vector<vector<pair<int,int>>>;
#define INF 1000000000000000000
#define MOD 1000000007

int main(){
  int N;
  cin>>N;
  vector<string> S(2);
  for(int i=0;i<N;i++){
    int T;
    char c;
    cin>>T>>c;
    S.at(T).push_back(c);
  }
  reverse(S.at(1).begin(),S.at(1).end());
  cout<<S.at(1)<<S.at(0)<<endl;
}