You're given a list of n strings a1, a2, ..., an. You'd like to concatenate them together in some order such that the resulting string would be lexicographically smallest.

Given the list of strings, output the lexicographically smallest concatenation.

Input

The first line contains integer n — the number of strings (1 ≤ n ≤ 5·104).

Each of the next n lines contains one string ai (1 ≤ |ai| ≤ 50) consisting of only lowercase English letters. The sum of string lengths will not exceed 5·104.

Output

Print the only string a — the lexicographically smallest string concatenation.

Examples

Input

4
abba
abacaba
bcd
er


Output

abacabaabbabcder


Input

5
x
xx
xxa
xxaa
xxaaa


Output

xxaaaxxaaxxaxxx


Input

3
c
cb
cba


Output

cbacbc
    	
    		
    		    /*
    		     * Author- Priyam Vora
    		     * BTech 2nd Year DAIICT
    		     */
    		     
    		            
    		    import java.io.*;
    		    import java.math.*;
    		    import java.util.*;
    		    import javax.print.attribute.SetOfIntegerSyntax;
    		     
    		    public class CodeMonk_Graph{
    		    	private static InputStream stream;
    		    	private static byte[] buf = new byte[1024];
    		    	private static int curChar;
    		    	private static int numChars;
    		    	private static SpaceCharFilter filter;
    		    	private static PrintWriter pw;
    		    	private static long count = 0,mod=1000000007;
    		    	private static TreeSet<Integer>ts[]=new TreeSet[200000];
    		    	private static HashSet hs=new HashSet();
    		     
    		        public static void main(String[] args) {
    		        	InputReader(System.in);
    		    		pw = new PrintWriter(System.out); 
    		            new Thread(null ,new Runnable(){
    		               public void run(){
    		                   try{
    		                       soln();
    		                       pw.close();
    		                   } catch(Exception e){
    		                       e.printStackTrace();
    		                   }
    		               }
    		           },"1",1<<26).start();
    		       }
    		    
    		    	public static long gcd(long x, long y) {
    		    		if (x == 0)
    		    			return y;
    		    		else
    		    			return gcd( y % x,x);
    		    	}
    		    	
    		    	private static int BinarySearch(int a[], int low, int high, int target) {
    		    		if (low > high)
    		    			return -1;
    		    		int mid = low + (high - low) / 2;
    		    		if (a[mid] == target)
    		    			return mid;
    		    		if (a[mid] > target)
    		    			high = mid - 1;
    		    		if (a[mid] < target)
    		    			low = mid + 1;
    		    		return BinarySearch(a, low, high, target);
    		    	}
    		    	
    		    	public static String reverseString(String s) {
    		    		StringBuilder sb = new StringBuilder(s);
    		    		sb.reverse();
    		    		return (sb.toString());
    		    	}
    		    	
    		    	public static long pow(long n, long p) {
    		    		if(p==0)
    		    			return 1;
    		    		if(p==1)
    		    			return n%mod;
    		    		if(p%2==0){
    		    			long temp=pow(n, p/2);
    		    		return (temp*temp)%mod;
    		    		}else{
    		    			 	long temp=pow(n,p/2);
    		    			 	temp=(temp*temp)%mod;
    		    			 	return(temp*n)%mod;
    		    			 	
    		    		}
    		    	}
    		     
    		    		
    		     
    		    	public static int[] radixSort(int[] f) {
    		    		int[] to = new int[f.length];
    		    		{
    		    			int[] b = new int[65537];
    		    			for (int i = 0; i < f.length; i++)
    		    				b[1 + (f[i] & 0xffff)]++;
    		    			for (int i = 1; i <= 65536; i++)
    		    				b[i] += b[i - 1];
    		    			for (int i = 0; i < f.length; i++)
    		    				to[b[f[i] & 0xffff]++] = f[i];
    		    			int[] d = f;
    		    			f = to;
    		    			to = d;
    		    		}
    		    		{
    		    			int[] b = new int[65537];
    		    			for (int i = 0; i < f.length; i++)
    		    				b[1 + (f[i] >>> 16)]++;
    		    			for (int i = 1; i <= 65536; i++)
    		    				b[i] += b[i - 1];
    		    			for (int i = 0; i < f.length; i++)
    		    				to[b[f[i] >>> 16]++] = f[i];
    		    			int[] d = f;
    		    			f = to;
    		    			to = d;
    		    		}
    		    		return f;
    		    	}
    		     
    		    	public static int nextPowerOf2(final int a) {
    		    		int b = 1;
    		    		while (b < a) {
    		    			b = b << 1;
    		    		}
    		    		return b;
    		    	}
    		     
    		    	public static boolean PointInTriangle(int p1, int p2, int p3, int p4, int p5, int p6, int p7, int p8) {
    		    		int s = p2 * p5 - p1 * p6 + (p6 - p2) * p7 + (p1 - p5) * p8;
    		    		int t = p1 * p4 - p2 * p3 + (p2 - p4) * p7 + (p3 - p1) * p8;
    		     
    		    		if ((s < 0) != (t < 0))
    		    			return false;
    		     
    		    		int A = -p4 * p5 + p2 * (p5 - p3) + p1 * (p4 - p6) + p3 * p6;
    		    		if (A < 0.0) {
    		    			s = -s;
    		    			t = -t;
    		    			A = -A;
    		    		}
    		    		return s > 0 && t > 0 && (s + t) <= A;
    		    	}
    		     
    		    	public static float area(int x1, int y1, int x2, int y2, int x3, int y3) {
    		    		return (float) Math.abs((x1 * (y2 - y3) + x2 * (y3 - y1) + x3 * (y1 - y2)) / 2.0);
    		    	}
    		     
    		    	public static boolean isPrime(int n) {
    		    		// Corner cases
    		    		if (n <= 1)
    		    			return false;
    		    		if (n <= 3)
    		    			return true;
    		     
    		    		// This is checked so that we can skip 
    		    		// middle five numbers in below loop
    		    		if (n % 2 == 0 || n % 3 == 0)
    		    			return false;
    		     
    		    		for (int i = 5; i * i <= n; i = i + 6)
    		    			if (n % i == 0 || n % (i + 2) == 0)
    		    				return false;
    		     
    		    		return true;
    		    	}
    		     
    		    	//merge Sort
    		     
    		    	static long sort(int a[])
    		    	{  int n=a.length;
    		    		int b[]=new int[n];	
    		    		return mergeSort(a,b,0,n-1);}
    		    	static long mergeSort(int a[],int b[],long left,long right)
    		    	{ long c=0;if(left<right)
    		    	 {   long mid=left+(right-left)/2;
    		    		 c= mergeSort(a,b,left,mid);
    		    		 c+=mergeSort(a,b,mid+1,right);
    		    		 c+=merge(a,b,left,mid+1,right); }	
    		    		return c;	 }
    		    	static long merge(int a[],int  b[],long left,long mid,long right)
    		    	{long c=0;int i=(int)left;int j=(int)mid; int k=(int)left;
    		    	while(i<=(int)mid-1&&j<=(int)right)
    		    	{ if(a[i]>a[j]) {b[k++]=a[i++]; }
    		    	else	{ b[k++]=a[j++];c+=mid-i;}}
    		    	while (i <= (int)mid - 1)   b[k++] = a[i++]; 
    		    	while (j <= (int)right) b[k++] = a[j++];
    		    	for (i=(int)left; i <= (int)right; i++) 
    		    		a[i] = b[i];  return c;  }
    		    	public static boolean isSubSequence(String large, String small, int largeLen, int smallLen) {
    		    		//base cases
    		    		if (largeLen == 0)
    		    			return false;
    		    		if (smallLen == 0)
    		    			return true;
    		    		// If last characters of two strings are matching
    		    		if (large.charAt(largeLen - 1) == small.charAt(smallLen - 1))
    		    			isSubSequence(large, small, largeLen - 1, smallLen - 1);
    		    		// If last characters are not matching
    		    		return isSubSequence(large, small, largeLen - 1, smallLen);
    		    	}
    		     
    		    	// To Get Input
    		    	// Some Buffer Methods
    		     
    		    	public static void InputReader(InputStream stream1) {
    		    		stream = stream1;
    		    	}
    		     
    		    	private static boolean isWhitespace(int c) {
    		    		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    		    	}
    		     
    		    	private static boolean isEndOfLine(int c) {
    		    		return c == '\n' || c == '\r' || c == -1;
    		    	}
    		     
    		    	private static int read() {
    		    		if (numChars == -1)
    		    			throw new InputMismatchException();
    		    		if (curChar >= numChars) {
    		    			curChar = 0;
    		    			try {
    		    				numChars = stream.read(buf);
    		    			} catch (IOException e) {
    		    				throw new InputMismatchException();
    		    			}
    		    			if (numChars <= 0)
    		    				return -1;
    		    		}
    		    		return buf[curChar++];
    		    	}
    		     
    		    	private static int nextInt() {
    		    		int c = read();
    		    		while (isSpaceChar(c))
    		    			c = read();
    		    		int sgn = 1;
    		    		if (c == '-') {
    		    			sgn = -1;
    		    			c = read();
    		    		}
    		    		int res = 0;
    		    		do {
    		    			if (c < '0' || c > '9')
    		    				throw new InputMismatchException();
    		    			res *= 10;
    		    			res += c - '0';
    		    			c = read();
    		    		} while (!isSpaceChar(c));
    		    		return res * sgn;
    		    	}
    		     
    		    	private static long nextLong() {
    		    		int c = read();
    		    		while (isSpaceChar(c))
    		    			c = read();
    		    		int sgn = 1;
    		    		if (c == '-') {
    		    			sgn = -1;
    		    			c = read();
    		    		}
    		    		long res = 0;
    		    		do {
    		    			if (c < '0' || c > '9')
    		    				throw new InputMismatchException();
    		    			res *= 10;
    		    			res += c - '0';
    		    			c = read();
    		    		} while (!isSpaceChar(c));
    		    		return res * sgn;
    		    	}
    		     
    		    	private static String nextToken() {
    		    		int c = read();
    		    		while (isSpaceChar(c))
    		    			c = read();
    		    		StringBuilder res = new StringBuilder();
    		    		do {
    		    			res.appendCodePoint(c);
    		    			c = read();
    		    		} while (!isSpaceChar(c));
    		    		return res.toString();
    		    	}
    		     
    		    	private static String nextLine() {
    		    		int c = read();
    		    		while (isSpaceChar(c))
    		    			c = read();
    		    		StringBuilder res = new StringBuilder();
    		    		do {
    		    			res.appendCodePoint(c);
    		    			c = read();
    		    		} while (!isEndOfLine(c));
    		    		return res.toString();
    		    	}
    		     
    		    	private static int[] nextIntArray(int n) {
    		    		int[] arr = new int[n];
    		    		for (int i = 0; i < n; i++) {
    		    			arr[i] = nextInt();
    		    		}
    		    		return arr;
    		    	}
    		     
    		    	private static int[][] next2dArray(int n, int m) {
    		    		int[][] arr = new int[n][m];
    		    		for (int i = 0; i < n; i++) {
    		    			for (int j = 0; j < m; j++) {
    		    				arr[i][j] = nextInt();
    		    			}
    		    		}
    		    		return arr;
    		    	}
    		    	private static char[][] nextCharArray(int n,int m){
    		    		char [][]c=new char[n][m];
    		    		for(int i=0;i<n;i++){
    		    			String s=nextLine();
    		    			for(int j=0;j<s.length();j++){
    		    				c[i][j]=s.charAt(j);
    		    			}
    		    		}
    		    		return c;
    		    	}
    		     
    		    	private static long[] nextLongArray(int n) {
    		    		long[] arr = new long[n];
    		    		for (int i = 0; i < n; i++) {
    		    			arr[i] = nextLong();
    		    		}
    		    		return arr;
    		    	}
    		     
    		    	private static void pArray(int[] arr) {
    		    		for (int i = 0; i < arr.length; i++) {
    		    			pw.print(arr[i] + " ");
    		    		}
    		    		pw.println();
    		    		return;
    		    	}
    		     
    		    	private static void pArray(long[] arr) {
    		    		for (int i = 0; i < arr.length; i++) {
    		    			pw.print(arr[i] + " ");
    		    		}
    		    		pw.println();
    		    		return;
    		    	}
    		     
    		    	private static void pArray(boolean[] arr) {
    		    		for (int i = 0; i < arr.length; i++) {
    		    			pw.print(arr[i] + " ");
    		    		}
    		    		pw.println();
    		    		return;
    		    	}
    		     
    		    	private static boolean isSpaceChar(int c) {
    		    		if (filter != null)
    		    			return filter.isSpaceChar(c);
    		    		return isWhitespace(c);
    		    	}
    		     
    		    	private interface SpaceCharFilter {
    		    		public boolean isSpaceChar(int ch);
    		    	}
    		
 //----------------------------------------My Code------------------------------------------------//
    		    	
    		    	private static void soln() {
    		    		int n=nextInt();
    		    	ArrayList<String> a=new ArrayList<String>();
    		    	for(int i=0;i<n;i++){
    		    		a.add(nextLine());
    		    	}
    		    	Collections.sort(a,new Comparator<String>() {

						@Override
						public int compare(String o1, String o2) {

							return (o1+o2).compareTo(o2+o1);
								
						}
					});
    		    	StringBuilder sb=new StringBuilder();
    		    	for(int i=0;i<n;i++){
    		    	//pw.println(a.get(i));
    		    		sb.append(a.get(i));
    		    	}
    		    	pw.println(sb);
    		    	}
    		    	
//-----------------------------------------The End--------------------------------------------------------------------------//
    		    }
    		    	
    		   
    		    
    			class Pair implements Comparable<Pair>{
    			   
    				int ind;
    				int len;
    				Pair(int ind,int len){
    					this.ind=ind;
    					this.len=len;
    				}
    				@Override
    				public int compareTo(Pair o) {
    					// TODO Auto-generated method stub
    				//	Sort in increasing order
    	return len-o.len;
    				}
    			
    			}
    		        class Graph{
    		        	private static int V,level[][],count=-1,lev_dfs[],degree=0,no_vert_conn_comp=0;
    		        	private Stack <Integer>st=new Stack();
    		        	private static LinkedList<Integer > adj[];
    		        	private boolean[][] Visite;
    		        	private static boolean [] Visited;
    		        	private static HashSet<Integer> Vis=new HashSet();
    		        	private static Stack<Integer> topo_sort=new Stack<>();
    		        	private static HashMap<String,Integer> hm=new HashMap<>();
    		  private static HashSet<String> hs=new HashSet();
    		private static HashSet<String > exist=new HashSet();	    
    			    	
    		    Graph(int V){
    		    V++;
    		    this.V=(V);
    		    adj=new LinkedList[V];
    		    Visite=new boolean[100][100];
    		    
    	 	    Visited=new boolean[V];
    		    level=new int[100][100];
    		    lev_dfs=new int[V]; 
    		   for(int i=0;i<V;i++)
    			   adj[i]=new LinkedList<Integer>();
    		
    		    }
    		    void setup(int n,int m){
    		    	//HashMap<String,Integer> hm=new HashMap<>();
    	    		int co=1;
    		    	for(int i=0;i<n;i++){
    	    			for(int j=0;j<m;j++){
    	    				String s="";
    	    				s+=(i)+" "+(j);
    	    				hm.put(s, co);
    	    			co++;
    	    			}
    	    		}
    		    }
    		   void addEdge(int v,int w){
    		    	
    			   String to="";
    			   to+=v+" "+w;
    			   exist.add(to);
    			   if(hs.contains(to))
    				   hs.remove(to);
    		    	if(adj[v]==null){
    		    		adj[v]=new LinkedList();
    		    	}
    		    	if(!adj[v].contains(w))
    		    	adj[v].add(w);
    		     if(adj[w]==null)
    		    	 adj[w]=new LinkedList();
    		     
    		     if(!adj[w].contains(v))
    		    	 adj[w].add(v);
    		    
    		     String s="";
    				  s+=(w)+" "+v;
    				  if(!exist.contains(s))
    				  hs.add(s);
    				  	
    		    }
    		  
    		 public static void top_ans(){
    		while(topo_sort.size()!=0)
    	{
    		System.out.print(hm.get(topo_sort.peek()));
    	topo_sort.pop();
    	}
    		
    		 }
    		 public static void topoSort(int startVert){
    			 if(!Vis.contains(startVert)){
    				 topoSortUtil(startVert);
    			 }
    		 }
    		    public static void topoSortUtil(int curr_Vert){
    		    	Vis.add(curr_Vert);
    		    	Iterator<Integer> it=adj[curr_Vert].listIterator();
    		    	
    		    	while(it.hasNext()){
    		    		int n=it.next();
    		   // 		System.out.println(n);
    		    		if(!Vis.contains(n)){
    		    			topoSortUtil(n);
    		    		}
    		    		
    		    	}
    		    	topo_sort.push(curr_Vert);
    		    }
    		    
    		    public static int BFS2(int startVert){
    		    	Visited=new boolean[V];
    		    	for(int i=1;i<V;i++){
    		    		lev_dfs[i]=-1;
    		    	}
    		    //	System.out.println(startVert);
    		    	Queue<Integer> q=new LinkedList<Integer>();
    		    	q.add(startVert);
    		    	
    		    	lev_dfs[startVert]=0;
    		    	while(!q.isEmpty()){
    		    		int top=q.poll();
    		    		
    		    		Iterator<Integer> i= adj[top].listIterator();
    		    		while(i.hasNext()){
    		    			int n=i.next();
    		    	//		System.out.println(top+" "+n);
    		    			if(!Visited[n]){
    		    				q.add(n);
    		    				Visited[n]=true;
    		    				lev_dfs[n]=lev_dfs[top]+1;
    		    			
    		    			}
    		    		}
    		    	}
    		    
    		    //	q.clear();
    		    	return -1;
    		    }
    		    public static int getAn(){
    		    	if(ans==Long.MAX_VALUE)
    		    		ans=-1;
    		    	return 0;
    		    }
    		    public int getEd(){
    		    	return degree/2;
    		    }
    		    public void get(int from,int to){
    		    	int h=lev_dfs[from]-lev_dfs[to];
    		    	if(h<=0){
    		    		System.out.println(-1);
    		    	}else{
    		    		System.out.println(h-1);
    		    	}
    		    }
    		    private static boolean check(int x,int y,char c[][]){
    			
    				if((x>=0 && y>=0) && (x<c.length && y<c[0].length) && c[x][y]!='#'){
    					
    					return true;
    				}
    				return false;
    			}
    		    public int BFS(int x,int y,int k,char[][] c)
    		    {
    		    	 LinkedList<Pair> queue = new LinkedList<Pair>();
    		        //Visited[s]=true;
    		   //     queue.add(new Pair(x,y));
    		       int count=0;
    		   level[x][y]=-1;
    		   c[x][y]='M';
    		        while (!queue.isEmpty())
    		        {
    		            Pair temp = queue.poll();
    		        
    		            
    		        }
    		        return V;
    		    }
    		    static long ans=Long.MAX_VALUE;
    		    
    		   public static void dfs2(int startVert,int endVert,long need){
    			Visited[startVert]=true;
    			//System.out.println(startVert+" "+need);
    			   for(int x:adj[startVert]){
    				if(x==endVert ){
    					String to="";
    					to+=startVert+" "+x;
    					
    					if(hs.contains(to) && startVert!=x)
    					ans=Math.min(need+1, ans);
    					else
    						ans=Math.min(need, ans);
    				}
    				else{
    					String to="";
    					to+=startVert+" "+x;
    					boolean tmp=false;
    					if(hs.contains(to) )
    						tmp=true;
    					if(!Visited[x])
    					{
    					if(tmp)
    						dfs2(x, endVert, need+1);
    					else{
    						dfs2(x, endVert, need);
    					}
    					}
    					}
    			}
    			   
    			   
    		   }
    		     public long dfs(int startVertex,int end){
    		    //	 getAns(startVertex);
    		    	 Visited=new boolean[V];
    		    	 if(!Visited[startVertex])  {
    		    
    		   return dfsUtil(startVertex,end);
    		    	//return getAns();
    		    	}
    		    	 
    		    
    		     
    		    return 0;
    		    	}
    		 private long dfsUtil(int startVertex,int end) {//0-Blue 1-Pink
    			 int c=1;
    		
    			 long cout=0;
    		      degree=0;
    		    	Visited[startVertex]=true;
    		    	lev_dfs[startVertex]=0;
    		      st.push(startVertex);
    		      int temp=-1;
    		      
    		    while(!st.isEmpty()){
    		    	
    		    	int top=st.pop();
    		    temp=Math.max(temp, top);
    		    //	ts.add(top);
    		    	Iterator<Integer> i=adj[top].listIterator();
    		     
    		    while(i.hasNext()){
    		    //	System.out.println(top);
    		    	int n=i.next();
    		     if( !Visited[n]){
    		    				Visited[n]=true;
    		    				String to="";
    		    				to+=
    		    			//	col_freq[col[n-1]]++;
    		    				c++;
    		    				st.push(n);
    		    					lev_dfs[n]=lev_dfs[top]+1;
    		    					if(n==end){
    		    	    				return lev_dfs[n];	
    		    	    				}
    		    		 }
    		         }
    		 }
    		 //   System.out.println(temp);
    		    if(lev_dfs[temp]+(end-temp)<=0){
    		    	return end-startVertex;
    		    }
    		    return Math.min(end-startVertex, lev_dfs[temp]+(end-temp));
    		    	
    		    }
    		        
    		        }     
    		       	        
    		    class Dsu{
    		    	private int rank[], parent[] ,n;
    		    	
    		    	Dsu(int size){
    		    		this.n=size+1;
    		    		rank=new int[n];
    		    		parent=new int[n];
    		    	makeSet();
    		    	}
    		    	
    		    	void makeSet(){
    		    		for(int i=0;i<n;i++){
    		    			parent[i]=i;
    		    		}
    		    	}
    		    	
    		    	int find(int x){
    		    		if(parent[x]!=x){
    		    			
    		    			parent[x]=find(parent[x]);
    		    		}
    		    		return parent[x];
    		    	}	
    		    	
    		    	void union(int x,int y){
    		    		int xRoot=find(x);
    		    		int yRoot=find(y);
    		    		
    		    		if(xRoot==yRoot)
    		    			return;
    		    		if(rank[xRoot]<rank[yRoot]){
    		    		parent[xRoot]=yRoot;	
    		    		}else if(rank[yRoot]<rank[xRoot]){
    		    			parent[yRoot]=xRoot;
    		    		}else{
    		    			parent[yRoot]=xRoot;
    		    			rank[xRoot]++;
    		    		}
    		    		
    		    	}
    		     
    		    }
    			  class Hashing {
    				 
    				  static final int multiplier = 43;
    				  static final Random rnd = new Random();
    				  static final int mod1 = BigInteger.valueOf((int) (1e9 + rnd.nextInt((int) 1e9))).nextProbablePrime().intValue();
    				  static final int mod2 = BigInteger.valueOf((int) (1e9 + rnd.nextInt((int) 1e9))).nextProbablePrime().intValue();
    				  static final int invMultiplier1 = BigInteger.valueOf(multiplier).modInverse(BigInteger.valueOf(mod1)).intValue();
    				  static final int invMultiplier2 = BigInteger.valueOf(multiplier).modInverse(BigInteger.valueOf(mod2)).intValue();
    		 
    				  long[] hash1, hash2;
    				  long[] inv1, inv2;
    				  int n;
    		 
    				  public Hashing(String s) {
    				    n = s.length();
    				    hash1 = new long[n + 1];
    				    hash2 = new long[n + 1];
    				    inv1 = new long[n + 1];
    				    inv2 = new long[n + 1];
    				    inv1[0] = 1;
    				    inv2[0] = 1;
    		 
    				    long p1 = 1;
    				    long p2 = 1;
    				    for (int i = 0; i < n; i++) {
    				      hash1[i + 1] = (hash1[i] + s.charAt(i) * p1) % mod1;
    				      p1 = p1 * multiplier % mod1;
    				      inv1[i + 1] = inv1[i] * invMultiplier1 % mod1;
    				      hash2[i + 1] = (hash2[i] + s.charAt(i) * p2) % mod2;
    				      p2 = p2 * multiplier % mod2;
    				      inv2[i + 1] = inv2[i] * invMultiplier2 % mod2;
    				    }
    				  }
    		 
    				  public long getHash(int i, int r) {
    					  i--;
    				    return (((hash1[r] - hash1[i] + mod1) * inv1[i] % mod1) << 32)
    				        + (hash2[r] - hash2[i] + mod2) * inv2[i] % mod2;
    				  }
    			}
    		    class MyComp implements Comparator<Long>{
    		        
    				@Override
    				public int compare(Long o1, Long o2) {
    					if(o1<o2){
    						return 1;
    					}else if(o1>o2){
    						return -1;
    					}
    					return 0;
    					
    				}
    		    }