#include<iostream>
#include<string>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<vector>
#include<utility>
#include<stack>
#include<queue>
#include<list>
#include<bitset>
#include<functional>

#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000
#define PI 3.14159265358979

using namespace std;
typedef pair<int, int> P;

int main(void) {
	string s;
	bool flag = true;
	bool check0 = true;
	bool check2 = true;
	int dp[27] = {};

	cin >> s;
	FOR(i, 0, 12) {
		dp[s[i] - 'a' + 1]++;
	}
	FOR(i, 14, 26) {
		if (dp[i] != 0) {
			flag = false;
			break;
		}
	}
	if (flag == false) {
		cout << "Impossible" << endl;
	}
	else {
		FOR(i, 1, 13) {
			if (dp[i] == 0) {
				if (check0 == false) {
					cout << "Impossible" << endl;
					break;
				}
				check0 = false;
			}
			if (dp[i] >= 2) {
				if (check2 == false) {
					cout << "Impossible" << endl;
				}
				check2 = false;
			}
		}
		if (check0 == true && check2 == true) {
			FOR(t, 1, 13) {
				char a;
				a = 'a' + t - 1;
				cout << a << endl;
			}
		}
		else {
			FOR(t, 1, 13) {
				if (dp[t] == 0) {
					char a;
					a = 'a' + t - 1;
					cout << a << endl;
					break;
				}
			}
		}
	}
	return 0;
}