#include <bits/stdc++.h>

using namespace std;

int main() {
    string s;
    cin >> s;

    vector<int> a(13);
    for (int i = 0; i < 13; ++i) {
        a[s[i] - 'a']++;
    }

    int cnt0 = 0, cnt1 = 0, cnt2 = 0, ans;
    for (int i = 0; i < 13; ++i) {
        switch (a[i]) {
            case 0:
                cnt0++;
                ans = i;
                break;
            case 1:
                cnt1++;
                break;
            case 2:
                cnt2++;
                break;
            default:
                break;
        }
    }

    if (cnt1 == 13) {
        for (int i = 0; i < 13; ++i) {
            cout << (char) ('a' + i) << endl;
        }
    } else if (cnt0 == 1 && cnt1 == 11 && cnt2 == 1) {
        cout << (char) ('a' + ans) << endl;
    } else {
        cout << "Impossible" << endl;
    }
    return 0;
}