#include <iostream>

#include <cstdio>

#include <cmath>

#include <algorithm>

#include <vector>

#include <iomanip>

#include <cstring>

#include <map>

#include <queue>

#include <set>

#include <cassert>

#include <stack>

#include <bitset>

#define mkp make_pair

using namespace std;

const double EPS=1e-;

typedef long long lon;

const lon SZ=,INF=0x7FFFFFFF,mod=;

void init()

{

}

void work()

{

}

bool cmp(string x,string y)

{

    for(int i=;i<x.size()&&i<y.size();++i)

    {

        if(x[i]<y[i])return ;

        else if(x[i]>y[i])return ;

    }

    string s1=x+y,s2=y+x;

    return s1<s2;

}

int main()

{

    std::ios::sync_with_stdio();

    //freopen("d:\\1.txt","r",stdin);

    lon casenum;

    //cin>>casenum;

    //cout<<casenum<<endl;

    //for(lon time=1;time<=casenum;++time)

    int n;

    for(int time=;cin>>n,n;++time)

    {

        vector<string> vct(n);

        for(int i=;i<n;++i)

        {

            cin>>vct[i];

        }

        sort(vct.begin(),vct.end(),cmp);

        for(int i=vct.size()-;i>=;--i)cout<<vct[i];

        cout<<endl;

    }

    return ;

}