#include <bits/stdc++.h>
#define REP(i, a, n) for(ll i = ((ll) a); i < ((ll) n); i++)
using namespace std;
typedef long long ll;

int main(void) {
    string S;
    cin >> S;
    sort(S.begin(), S.end());
    S.push_back('o');
    bool pair = false;
    bool ans = true;
    char temp = 'a';
    char lost = '\0';
    int memo = 0;
    REP (i, 0, 13) {
        if (S[i] != (char)(temp + memo + i)) {
            if (lost != '\0') {
                ans = false;
                break;
            }
            lost = (char)(temp + memo + i);
            memo++;
        }
        if (S[i] == S[i+1]) {
            if (pair) {
                ans = false;
                break;
            }
            pair = true;
            memo--;
        }
    }
    if (!ans) cout << "Impossible" << endl;
    else if (pair) cout << lost << endl;
    else REP(i, 0, 13) cout << S[i] << endl;
    return 0;
}