#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>
#include<limits>

#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()

using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ll, string> pls;

map<char, int> m;
string str = "abcdefghijklm";

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

	for (int i = 0; i < s.size(); i++) {
		m[s[i]]++;
	}

	int cnt = 0;
	char c=' ';
	for (int i = 0; i < str.size(); i++) {
		cnt += m[str[i]];
		if (m[str[i]] == 0) {
			c = str[i];
		}
	}

	if (cnt < 12) {
		cout << "Impossible" << endl;
	}else{
		if (c == ' ') {
			for (int i = 0; i < str.size(); i++)
				cout << str[i] << endl;
		}
		else
			cout << c << endl;
	}
	return 0;
}