[sth]xx

#include <iostream>
#include <map>
#include <vector>
#include <string>


using namespace std;

int main(){
    string s;
    char key;
    char value;
    map<char, vector<char> > map_level1;
    map<char, vector<char> > map_level2;
    while (getline(cin, s)){
        if (s == "eof"){
            break;
        }
        key = s[0];
        value = s[2];
        //not in both
        if (map_level1.find(key) == map_level1.end() && map_level2.find(key) == map_level2.end()){
            map_level1[key].push_back(value);
            map_level2[value];
        }else if (map_level1.find(key) == map_level1.end()){ //key only in map2
            map_level2[key].push_back(value);

        }else //key only in map1
        {
            map_level1[key].push_back(value); //only in map1
            if (map_level2.find(value) == map_level2.end()){ //value not in map2
                map_level2[value];
            }
        }
    }

    map<char, vector<char> >::iterator it = map_level1.begin();
    map<char, vector<char> >::iterator it_end = map_level1.end();
    for (; it != it_end; it++){
        cout << it->first << endl;

        //vec in level1 
        for (int i = 0; i < map_level1[it->first].size(); i++){
            cout <<"  "<< map_level1[it->first][i] << endl;

            //in map2
            if (map_level2.find(map_level1[it->first][i]) != map_level2.end()){
                for (int j = 0; j < map_level2[map_level1[it->first][i]].size(); j++){
                    cout <<"    "<< map_level2[map_level1[it->first][i]][j] << endl;
                }
            }

        }

    }

    getchar();

    return 0;
}