#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

string s[100005];
int n;

bool cmp(string x,string y)
{
    string X = x+y,Y = y+x;
    return X > Y;
}

int main()
{
    while(cin >> n)
    {
        for(int i = 1;i <= n;i++)    cin >> s[i];
        sort(s+1,s+1+n,cmp);
        for(int i = 1;i <= n;i++)    cout << s[i];
        cout << endl;
    }
    return 0;
}