#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <string>
using namespace std;
 
void parse_string(vector <set <string> > &result) {
    map<char, vector<string>> temp;
    string word;
    while(cin >> word){
    	temp[word[0]].push_back(word);
    }
    for(auto p : temp){
    	set<string> t;
    	for(auto w : p.second){
    		t.insert(w);
    	}
    	result.push_back(t);
    }
    for(auto p : result){
    	for(auto t : p){
    		cout << t << " ";
    	}
    	cout << endl;
    }
}
 
int main() {
	vector <set <string> > result;
	parse_string(result);
	return 0;
}

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