#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)




#define ZERO(a) memset(a,0,sizeof(a))
class SCC {
public:
	static const int MV = 5000;
	vector<vector<int> > SC; int NV, GR[MV], rev[MV];
private:
	vector<int> E[MV], RE[MV], NUM; int vis[MV];
public:
	void init(int NV) { this->NV = NV; for (int i = 0; i<MV; i++) { E[i].clear(); RE[i].clear(); } }
	void add_edge(int x, int y) { E[x].push_back(y); RE[y].push_back(x); }
	void dfs(int cu) { vis[cu] = 1; for (int i = 0; i<E[cu].size(); i++) if (!vis[E[cu][i]]) dfs(E[cu][i]); NUM.push_back(cu); }
	void revdfs(int cu, int ind) {
		int i; vis[cu] = 1; GR[cu] = ind; SC[ind].push_back(cu); rev[cu] = ind;
		rep(i, 0, RE[cu].size()) if (!vis[RE[cu][i]]) revdfs(RE[cu][i], ind);
	}
	void scc() {
		int c = 0; SC.clear(); SC.resize(MV); NUM.clear();
		ZERO(vis); for (int i = 0; i<NV; i++) if (!vis[i]) dfs(i);
		ZERO(vis); for (int i = NUM.size() - 1; i >= 0; i--) if (!vis[NUM[i]]) {
			SC[c].clear(); revdfs(NUM[i], c); sort(SC[c].begin(), SC[c].end()); c++;
		}
		SC.resize(c);
	}
};
class TwoSat {
	int NV;
	SCC sc;
public:
	vector<int> val;
	void init(int NV) { this->NV = NV * 2; sc.init(NV * 2); val.resize(NV); }
	void add_edge(int x, int y) { // k+0:normal k+NV:inverse
		sc.add_edge((x + NV / 2) % NV, y);
		sc.add_edge((y + NV / 2) % NV, x);
	}
	bool sat() { // empty:false 
		sc.scc();
		for (int i = 0; i<NV / 2; i++) if (sc.GR[i] == sc.GR[i + NV / 2]) return false;
		for (int i = 0; i<NV / 2; i++) val[i] = sc.GR[i]>sc.GR[i + NV / 2];
		return true;
	}
};
//-----------------------------------------------------------------
TwoSat ts;
int N;
string S[1010];
//-----------------------------------------------------------------
int main() {
	cin >> N;
	if (100 < N) {
		printf("Impossible\n");
		return 0;
	}
	rep(i, 0, N) cin >> S[i];

	ts.init(N);
	rep(i, 0, N) rep(j, i + 1, N) {
		rep(ii, 1, 3) rep(jj, 1, 3) {
			set<string> s;
			s.insert(S[i].substr(0, ii));
			s.insert(S[i].substr(ii));
			s.insert(S[j].substr(0, jj));
			s.insert(S[j].substr(jj));

			if (s.size() != 4) {
				int a = i, b = j;
				if (ii == 1) a += N;
				if (jj == 1) b += N;
				ts.add_edge(a, b);
			}
		}
	}

	if (!ts.sat()) {
		printf("Impossible\n");
		return 0;
	}

	rep(i, 0, N) {
		int len = 1;
		if (ts.val[i] == 0) len++;

		printf("%s %s\n", S[i].substr(0, len).c_str(), S[i].substr(len).c_str());
	}
}