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

long long gcd(long long x, long long y)
{
    if (y == 0)
        return x;
    return gcd(y, x % y);
}

long long lcm(long long x, long long y)
{
    if (x == 0 || y == 0)
        return 0;
    return x / gcd(x, y) * y;
}

const string ss = "abcdefghijklm";

int main()
{
    string s;
    cin >> s;
    map<char, int> mp;
    for (int i = 0; i < 13; i++)
    {
        mp[s[i]] = 1;
    }
    int cnt = 0;
    for (int i = 0; i < 13; i++)
    {
        cnt += mp[ss[i]];
    }
    if (cnt == 13)
    {
        for (int i = 0; i < 13; i++)
        {
            cout << ss[i] << endl;
        }
    }
    else if (cnt == 12)
    {
        for (int i = 0; i < 13; i++)
        {
            if (mp[ss[i]] == 0)
            {
                cout << ss[i] << endl;
                break;
            }
        }
    }
    else
    {
        cout << "Impossible" << endl;
    }
}