#include <bits/stdc++.h>

using namespace std;

#define forsn(i, s, n) for(int i=s;i<int(n);i++)
#define forn(i, n) forsn(i, 0, n)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define NACHO ios_base::sync_with_stdio(0);cin.tie(NULL);

typedef long long tint;

struct Trie{
    map<char, Trie> arbol;
    bool finPalabra = false;
};

bool encontrado = 1;
string s;
int tamPalabra;

void insertar(Trie &t, int pos) {
    if(pos < tamPalabra){
        if(pos == tamPalabra-1) t.finPalabra = true;
        insertar(t.arbol[s[pos]], pos+1);
    }
}

bool consistent = 1;

void recorrer(Trie t, string palabra){
    if(t.finPalabra && t.arbol.size() > 0){ consistent = 0; cout << palabra << endl;}
    for(auto &i:t.arbol) {
        recorrer(i.second, palabra+i.first);
    }
}

int main(){
    int n; cin >> n;
    Trie t;
    vector<string> strs (n);
    forn(i, n){
        cin >> s;
        strs[i] = s;
        tamPalabra = int(s.size())+1;
        insertar(t, 0);
    }
    recorrer(t, "");
    cout << consistent << "\n";
}
//