package adv2016;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class N470_2 {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni();
		char[][] u = new char[n][];
		for(int i = 0;i < n;i++){
			u[i] = ns(3);
		}
		if(n > 52){
			out.println("Impossible");
			return;
		}
		int[] from = new int[n*n*4];
		int[] to = new int[n*n*4];
		int p = 0;
		for(int i = 0;i < n;i++){
			for(int j = i+1;j < n;j++){
				for(int k = 0;k < 2;k++){
					for(int l = 0;l < 2;l++){
						int indk = k == 0 ? 0 : 2;
						int indl = l == 0 ? 0 : 2;
						int iind = k == 0 ? i : i+n;
						int iindi = 2*i+n-iind;
						int jind = l == 0 ? j : j+n;
						int jindi = 2*j+n-jind;
						int xk = k == 0 ? 1 : 0;
						int xl = l == 0 ? 1 : 0;
						if(u[i][indk] == u[j][indl] || u[i][xk] == u[j][xl] && u[i][xk+1] == u[j][xl+1]){
							from[p] = iind; to[p] = jindi; p++;
							from[p] = jind; to[p] = iindi; p++;
						}
					}
				}
			}
		}
		int[][] g = packD(2*n, from, to, p);
		int[] sign = restore2SAT(g);
		if(sign == null){
			out.println("Impossible");
			return;
		}
		
		for(int i = 0;i < n;i++){
			if(sign[i] == 1){
				out.println(u[i][0] + " " + u[i][1] + u[i][2]);
			}else{
				out.println("" + u[i][0] + u[i][1] + " " + u[i][2]);
			}
		}
	}
	
	public static int[] restore2SAT(int[][] g)
	{
		assert g.length % 2 == 0;
		int n = g.length/2;
		int[] clus = decomposeToSCC(g);
		int[] ret = new int[n];
		for(int i = 0;i < n;i++){
			if(clus[i] == clus[i+n])return null; // unsatisfied
			ret[i] = clus[i] > clus[i+n] ? -1 : 1;
		}
		return ret;
	}
	
	public static int[] decomposeToSCC(int[][] g)
	{
		int n = g.length;
		int[] stack = new int[n+1];
		int[] ind = new int[n+1];
		int[] ord = new int[n];
		Arrays.fill(ord, -1);
		int[] low = new int[n];
		Arrays.fill(low, -1);
		int sp = 0;
		int id = 0; // preorder
		int[] clus = new int[n];
		int cid = 0;
		int[] cstack = new int[n+1];
		int csp = 0;
		boolean[] incstack = new boolean[n];
		for(int i = 0;i < n;i++){
			if(ord[i] == -1){
				ind[sp] = 0;
				cstack[csp++] = i;
				stack[sp++] = i;
				incstack[i] = true;
				while(sp > 0){
					int cur = stack[sp-1];
					if(ind[sp-1] == 0){
						ord[cur] = low[cur] = id++;
					}
					if(ind[sp-1] < g[cur].length){
						int nex = g[cur][ind[sp-1]];
						if(ord[nex] == -1){
							ind[sp-1]++;
							ind[sp] = 0;
							incstack[nex] = true;
							cstack[csp++] = nex;
							stack[sp++] = nex;
						}else{
							// shortcut
//							U.tr(cur, nex, incstack[nex], low[nex], stack);
							if(incstack[nex])low[cur] = Math.min(low[cur], low[nex]);
							ind[sp-1]++;
						}
					}else{
						if(ord[cur] == low[cur]){
							while(csp > 0){
								incstack[cstack[csp-1]] = false;
								clus[cstack[--csp]] = cid;
								if(cstack[csp] == cur)break;
							}
							cid++;
						}
						if(--sp >= 1)low[stack[sp-1]] = Math.min(low[stack[sp-1]], low[stack[sp]]);
					}
				}
			}
		}
		return clus;
	}

	
	public static int[][] packD(int n, int[] from, int[] to){ return packD(n, from, to, from.length);}
	public static int[][] packD(int n, int[] from, int[] to, int sup)
	{
		int[][] g = new int[n][];
		int[] p = new int[n];
		for(int i = 0;i < sup;i++)p[from[i]]++;
		for(int i = 0;i < n;i++)g[i] = new int[p[i]];
		for(int i = 0;i < sup;i++){
			g[from[i]][--p[from[i]]] = to[i];
		}
		return g;
	}

	
	void run() throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//		Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){
//			@Override
//			public void run() {
//				long s = System.currentTimeMillis();
//				solve();
//				out.flush();
//				if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//			}
//		};
//		t.start();
//		t.join();
	}
	
	public static void main(String[] args) throws Exception { new N470_2().run(); }
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private long[] nal(int n)
	{
		long[] a = new long[n];
		for(int i = 0;i < n;i++)a[i] = nl();
		return a;
	}
	
	private char[][] nm(int n, int m) {
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[][] nmi(int n, int m) {
		int[][] map = new int[n][];
		for(int i = 0;i < n;i++)map[i] = na(m);
		return map;
	}
	
	private int ni() { return (int)nl(); }
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}