#include <bits/stdc++.h>


using namespace std;
typedef long long ll;
#define REP(i,n) for(int i=0; i<int(n); i++)
#define FOR(i,m,n) for(int i=int(m); i<int(n); i++)
#define ALL(obj) (obj).begin(),(obj).end()
#define VI vector<int>
#define VLL vector<long long>
#define VVI vector<vector<int>>
#define VVLL vector<vector<long long>>
#define VC vector<char>
#define VS vector<string>
#define VVC vector<vector<char>>
#define VB vector<bool>
#define VVB vector<vector<bool>>
#define fore(i,a) for(auto &i:a)

typedef pair <int, int> P;
template<class T> bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }
const int  INF = 1 << 29;
const ll INFL = 1LL << 60;
const ll mod = 1000000007;





int main() {

	string s;
	cin >> s;
	VI a(13, 0);
	REP(i, 13) {
		if (s[i] > 'm') {
			cout << "Impossible" << endl;
			return 0;
		}
		a[s[i] - 'a']++;
	}
	bool b = true;
	REP(i, 13) {
		if (a[i] > 2) {
			cout << "Impossible" << endl;
			return 0;
		}
		if (a[i] == 2 && !b) {
			cout << "Impossible" << endl;
			return 0;
		}
		if (a[i] == 2)b = false;
	}
	if (b) {
		REP(i, 13) {
			cout << (char)('a' + i) << endl;
		}
	}
	else {
		REP(i, 13) {
			if (a[i] == 0) {
				cout << (char)('a' + i) << endl;

			}
		}
	}

	
}