#include #include #include #include #include #include #include #include #include using namespace std; int main() { string s; int cnt[26] = { 0 }; cin >> s; for (int i = 0; i < 13; ++i) { cnt[s[i] - 'a']++; if (cnt[s[i] - 'a'] > 2) { cout << "Impossible" << endl; return 0; } } for (int i = 0; i < 13; ++i) { if (cnt[i] == 0) { cout << (char)(i + 'a') << endl; return 0; } } for (int i = 0; i < 13; ++i) { cout << (char)(i + 'a') << endl; } return 0; }