#include <iostream>
#include <cstdlib>
#include <map>
#include <vector>
#include <algorithm>

using namespace std;

map <string, int> used;
map < string , map <string, int> > nodes;
vector <string> groups;

void findgroups(string node,int level) {
   if (!used[node]) {
       if (level == 0 ) groups.push_back("");
       used[node] = 1;
       groups.back() += node;
       
       map <string, int>::iterator jt;
       for (jt = nodes[node].begin(); jt != nodes[node].end() ; jt++) {
            findgroups(jt->first,level+1);
       }
    }
}


int main() {
        
    int n;    
    cin >> n;
    
    string src, ref;
    for (int i = 0 ; i < n ; i++) {
        cin >> src >> ref;
        used[src] = used[ref] = 0;
        nodes[src][ref] = nodes[ref][src] = 1;
    }
 
   map < string , int >::iterator nk; 
   for (nk = used.begin() ; nk != used.end(); nk++) {
        findgroups(nk->first,0);
   }

   vector <string>::iterator git;   
   sort(groups.begin(),groups.end());
   for (git = groups.begin(); git != groups.end(); git++) {
        sort(git->begin(),git->end());
        cout << *git << endl;
    }

    // system("pause");
    
    return 0;    
}