#include <iostream>
#include <string>
#include <vector>
#include <set>

using namespace std;

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

	vector<set<char>> alpha(3);
	for (char c : string("abcdefghijklm")) {
		alpha[0].insert(c);
	}

	bool ok = true;
	for (auto c : s) {
		cout << c << endl;
		if (alpha[2].count(c) > 0) {
			ok = false;
			break;
		} else if (alpha[1].count(c) > 0) {
			alpha[1].erase(c);
			alpha[2].insert(c);
		} else if (alpha[0].count(c) > 0) {
			alpha[0].erase(c);
			alpha[1].insert(c);
		} else {
			alpha[0].insert(c);
		}
	}

	if (alpha[2].size() > 1 || alpha[0].size() > 1) {
		ok = false;
	}

	if (ok) {
		int idx = alpha[0].size() == 1 ? 0 : 1;
		for (auto c : alpha[idx]) {
			cout << c << endl;
		}
	} else {
		cout << "Impossible" << endl;
	}
	return 0;
}