import java.io.*;
import java.util.*;


public class Main_yukicoder470_1 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		char[][] u = new char[n][];
		for (int i = 0; i < n; i++) {
			u[i] = sc.next().toCharArray();
		}

		if (n > 52) {
			pr.println("Impossible");
			return;
		}

		int V = n * 2;
		SCC scc = new SCC(V);

		for (int i = 0; i < n; i++) {
			for (int j = i + 1; j < n; j++) {
				if (u[i][0] == u[j][0]) {
					scc.add_edge(i, j + n);
					scc.add_edge(j, i + n);
				}
				if (u[i][1] == u[j][1] && u[i][2] == u[j][2]) {
					scc.add_edge(i, j + n);
					scc.add_edge(j, i + n);
				}

				if (u[i][2] == u[j][2]) {
					scc.add_edge(i + n, j);
					scc.add_edge(j + n, i);
				}
				if (u[i][0] == u[j][0] && u[i][1] == u[j][1]) {
					scc.add_edge(i + n, j);
					scc.add_edge(j + n, i);
				}

				if (u[i][0] == u[j][2]) {
					scc.add_edge(i, j);
					scc.add_edge(j + n, i + n);
				}
				if (u[i][1] == u[j][0] && u[i][2] == u[j][1]) {
					scc.add_edge(i, j);
					scc.add_edge(j + n, i + n);
				}

				if (u[i][2] == u[j][0]) {
					scc.add_edge(i + n, j + n);
					scc.add_edge(j, i);
				}
				if (u[i][0] == u[j][1] && u[i][1] == u[j][2]) {
					scc.add_edge(i + n, j + n);
					scc.add_edge(j, i);
				}
			}
		}

		scc.scc();

		for (int i = 0; i < n; i++) {
			if (scc.cmp[i] == scc.cmp[i + n]) {
				pr.println("Impossible");
				return;
			}
		}

		for (int i = 0; i < n; i++) {
			if (scc.cmp[i] > scc.cmp[i + n]) {
				pr.printf("%c %c%c\n", u[i][0], u[i][1], u[i][2]);
			} else {
				pr.printf("%c%c %c\n", u[i][0], u[i][1], u[i][2]);
			}
		}
	}

	// SCC O(V + E)
	private static class SCC {
		private int V;
		private List<List<Integer>> edges;
		private List<List<Integer>> redges;  // 逆向きの辺
		private List<Integer> vs;  // 帰りがけ順の並び
		private int[] used;  // 0:White, 1:Gray, 2:Black
		private int[] cmp;  // 属する強連結成分のトポロジカル順序

		private SCC(int V) {
			this.V = V;

			edges = new ArrayList<>(V);
			redges = new ArrayList<>(V);
			for (int i = 0; i < V; i++) {
				edges.add(new ArrayList<>());
				redges.add(new ArrayList<>());
			}
			vs = new ArrayList<>(V);
			used = new int[V];
			cmp = new int[V];
		}

		private void add_edge(int from, int to) {
			edges.get(from).add(to);
			redges.get(to).add(from);
		}

		private int scc() {
			// dfs
			for (int v = 0; v < V; v++) {
				if (used[v] != 0) {
					continue;
				}

				Deque<Integer> st = new ArrayDeque<>();
				st.push(v);
				while (!st.isEmpty()) {
					int e = st.peek();

					if (used[e] == 2) {
						st.pop();
					} else if (used[e] == 1) {
						// postorder
						vs.add(e);
						used[e] = 2;
						st.pop();
					} else {
						// preorder
						used[e] = 1;
						for (int next : edges.get(e)) {
							if (used[next] == 2) {
								// 前進辺または横断辺
								continue;
							} else if (used[next] == 1) {
								// 後退辺
								continue;
							}

							st.push(next);
						}
					}
				}
			}

			Arrays.fill(used, 0);

			// rdfs
			int k = 0;
			for (int i = vs.size() - 1; i >= 0; i--) {
				int v = vs.get(i);

				if (used[v] != 0) {
					continue;
				}

				Deque<Integer> st = new ArrayDeque<>();
				st.push(v);
				while (!st.isEmpty()) {
					int e = st.peek();

					if (used[e] == 2) {
						st.pop();
					} else if (used[e] == 1) {
						// postorder
						used[e] = 2;
						st.pop();
					} else {
						// preorder
						cmp[e] = k;
						used[e] = 1;
						for (int next : redges.get(e)) {
							if (used[next] == 2) {
								// 前進辺または横断辺
								continue;
							} else if (used[next] == 1) {
								// 後退辺
								continue;
							}

							st.push(next);
						}
					}
				}

				k++;
			}

			return k;
		}

		// v が属する強連結成分のトポロジカル順序
		private int getCmp(int v) {
			return cmp[v];
		}
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);

		solve();

		pr.close();
		sc.close();
	}

	@SuppressWarnings("unused")
	private static class Scanner {
		BufferedReader br;

		Scanner (InputStream in) {
			br = new BufferedReader(new InputStreamReader(in));
		}

		private boolean isPrintable(int ch) {
			return ch >= '!' && ch <= '~';
		}

		private boolean isCRLF(int ch) {
			return ch == '\n' || ch == '\r' || ch == -1;
		}

		private int nextPrintable() {
			try {
				int ch;
				while (!isPrintable(ch = br.read())) {
					if (ch == -1) {
						throw new NoSuchElementException();
					}
				}

				return ch;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		String next() {
			try {
				int ch = nextPrintable();
				StringBuilder sb = new StringBuilder();
				do {
					sb.appendCodePoint(ch);
				} while (isPrintable(ch = br.read()));

				return sb.toString();
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		int nextInt() {
			try {
				// parseInt from Integer.parseInt()
				boolean negative = false;
				int res = 0;
				int limit = -Integer.MAX_VALUE;
				int radix = 10;

				int fc = nextPrintable();
				if (fc < '0') {
					if (fc == '-') {
						negative = true;
						limit = Integer.MIN_VALUE;
					} else if (fc != '+') {
						throw new NumberFormatException();
					}
					fc = br.read();
				}
				int multmin = limit / radix;

				int ch = fc;
				do {
					int digit = ch - '0';
					if (digit < 0 || digit >= radix) {
						throw new NumberFormatException();
					}
					if (res < multmin) {
						throw new NumberFormatException();
					}
					res *= radix;
					if (res < limit + digit) {
						throw new NumberFormatException();
					}
					res -= digit;

				} while (isPrintable(ch = br.read()));

				return negative ? res : -res;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		long nextLong() {
			try {
				// parseLong from Long.parseLong()
				boolean negative = false;
				long res = 0;
				long limit = -Long.MAX_VALUE;
				int radix = 10;

				int fc = nextPrintable();
				if (fc < '0') {
					if (fc == '-') {
						negative = true;
						limit = Long.MIN_VALUE;
					} else if (fc != '+') {
						throw new NumberFormatException();
					}
					fc = br.read();
				}
				long multmin = limit / radix;

				int ch = fc;
				do {
					int digit = ch - '0';
					if (digit < 0 || digit >= radix) {
						throw new NumberFormatException();
					}
					if (res < multmin) {
						throw new NumberFormatException();
					}
					res *= radix;
					if (res < limit + digit) {
						throw new NumberFormatException();
					}
					res -= digit;

				} while (isPrintable(ch = br.read()));

				return negative ? res : -res;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		float nextFloat() {
			return Float.parseFloat(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		String nextLine() {
			try {
				int ch;
				while (isCRLF(ch = br.read())) {
					if (ch == -1) {
						throw new NoSuchElementException();
					}
				}
				StringBuilder sb = new StringBuilder();
				do {
					sb.appendCodePoint(ch);
				} while (!isCRLF(ch = br.read()));

				return sb.toString();
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		void close() {
			try {
				br.close();
			} catch (IOException e) {
//				throw new NoSuchElementException();
			}
		}
	}

	private static class Printer extends PrintWriter {
		Printer(PrintStream out) {
			super(out);
		}
	}
}