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

typedef long long ll;

int main() {
    int n;
    cin >> n;
    vector<int> a(26);
    vector<string> S(n);
    bool flag = false;
    for(int i = 0; i < n; ++i) {
        string x;
        cin >> x;
        if (x[0] == x[1] || x[1] == x[2] || x[2] == x[0]) flag = true;
        a[x[0] - 'a'] = 1;
        a[x[1] - 'a'] = 1;
        a[x[2] - 'a'] = 1;
        S[i] = x;
    }

    int sum = 0;
    for(int i = 0; i < 26; ++i) sum += a[i];

    if (flag || sum > 18) {cout << 0 << "\n"; return 0;}

    for(int i = 0; i < 26 && sum < 18; ++i) {
        if (a[i] == 0) {a[i] = 1; sum++;}
    }

    vector<char> b;
    map<char, int> m;
    for(int i = 0; i < 26; ++i) if (a[i] == 1) {b.push_back('a' + i); m['a' + i] = b.size() - 1;}

    for (int x1 = 0; x1 < 13; ++x1) {
        for (int x2 = x1 + 1; x2 < 14; ++x2) {
            for (int x3 = x2 + 1; x3 < 15; ++x3) {
                for(int x4 = x3 + 1; x4 < 16; ++x4) {
                    for(int x5 = x4+1; x5 < 17; ++x5) {
                        for(int x6 = x5+1; x6 < 18; ++x6) {
                            set<char> s1;
                            s1.insert(x1);
                            s1.insert(x2);
                            s1.insert(x3);
                            s1.insert(x4);
                            s1.insert(x5);
                            s1.insert(x6);
                            for (int y1 = 1; y1 < 13; ++y1) {
                                if (s1.count(y1)==1) continue;
                                for(int y2 = y1 +1; y2 < 14; ++y2) {
                                    if (s1.count(y2) == 1) continue;
                                    for(int y3 = y2+1; y3 < 15; ++y3) {
                                        if (s1.count(y3) == 1) continue;
                                        for(int y4 = y3+1; y4 <16; ++y4) {
                                            if (s1.count(y4)==1) continue;
                                            for(int y5 = y4+1; y5 < 17; ++y5) {
                                                if (s1.count(y5)==1) continue;
                                                for(int y6=y5+1; y6 < 18; ++y6) {
                                                    if (s1.count(y6) == 1) continue;
                                                    set<char> s2;
                                                    s2.insert(y1);
                                                    s2.insert(y2);
                                                    s2.insert(y3);
                                                    s2.insert(y4);
                                                    s2.insert(y5);
                                                    s2.insert(y6);
                                                    bool work = true;
                                                    for(string& v: S) {
                                                        int X = 0, Y = 0;
                                                        for(char& c: v)
                                                            if (s1.count(m[c])==1) X++;
                                                            else if (s2.count(m[c])==1) Y++;
                                                        if (X != 1 || Y != 1) {work = false; break;}
                                                    }
                                                    if (work) {
                                                        string ok1 = string(1, b[x1]) + b[x2] + b[x3] + b[x4] + b[x5] + b[x6];
                                                        string ok2 = string(1, b[y1]) + b[y2] + b[y3] + b[y4] + b[y5] + b[y6];
                                                        string ok3 = "";
                                                        for(int z = 0; z < 18; ++z)
                                                            if (s1.count(z)==0 && s2.count(z)==0)
                                                                ok3 = ok3 + b[z];
                                                        cout << ok1 << " " << ok2 << " " << ok3 << "\n";
                                                        return 0;
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
        cout << "0\n"; return 0;
    }

}