#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<iomanip>
using namespace std;
template<typename T>inline void QR(T& x){
	char ch;bool f=0;
	while(ch=getchar(),(ch<'0'||ch>'9')&&ch!='-');
	if(ch=='-'){f=1;ch=getchar();}x=ch-48;
	while(ch=getchar(),ch>='0'&&ch<='9')x=x*10+ch-48;
	if(f)x=-x;
}
template<typename T>inline void QW(T x){
	char str[30];short cnt=0;
	if(x<0){putchar('-');x=-x;}
	while(str[+cnt]=x%10+48,x/=10);
	while(putchar(str[cnt]),--cnt);
}
const int maxn=1100;
inline bool com(const string& a,const string& b){
	return a+b>b+a;
}
string str[maxn];
int main(){
	#define submit
	#ifdef submit
	    freopen("brick.in","r",stdin);
	    freopen("brick.out","w",stdout);
	#endif
	int n;
	scanf("%d",&n);
	for(int i=1;i<=n;i++)cin>>str[i];
	sort(str+1,str+1+n,com);
	for(int i=1;i<=n;++i){
		cout<<str[i];
	}putchar(10);
	#ifdef submit
	    fclose(stdin);
	    fclose(stdout);
	#else
	    system("pause");
	#endif
	return 0;
}