#include <bits/stdc++.h>
using namespace std;

int main(){
  vector<int> edge[26]={};
  int deps[26]={};

  int nc; cin>>nc;
  while (nc--){
    char a,b,c; cin>>a>>c>>b;
    a-='a'; assert(0<=a and a<26);
    b-='a'; assert(0<=b and b<26);
    assert(c=='<' or c=='>');
    if (c=='>') swap(a,b);
    edge[a].push_back(b);
    ++deps[b];
  }

  string s; cin>>s;

  int have[26]={};
  for (char c: s)
    have[c-'a']++;

  vector<int> todo;
  for (int i=0; i<26; i++)
    if (not deps[i])
      todo.push_back(i);

  string t;
  for (int i=0; i<todo.size(); i++){
    for (int j=have[todo[i]]; j--;){
      t+=char(todo[i]+'a');
    }
    for (int k: edge[todo[i]]){
      if (not --deps[k]){
        todo.push_back(k);
      }
    }
  }

  if (t.size()==s.size()){
    cout<<t<<endl;
  }else{
    cout<<"IMPOSSIBLE"<<endl;
  }
}