#include <algorithm>

#include <cassert>

#include <cmath>

#include <cstdio>

#include <cstring>

#include <iostream>

#include <map>

#include <queue>

#include <set>

#include <string>

#include <tuple>

#define LOCAL_DEBUG

using namespace std;

typedef pair<double, long long> MyPair;

const int MAXN = ;

long long base[];

string a[MAXN];

bool cmp(string s1, string s2) {

    return s1 + s2 < s2 + s1;

}

int main() {

#ifdef LOCAL_DEBUG

    freopen("C:\\Users\\Iris\\source\\repos\\ACM\\ACM\\input.txt", "r", stdin);

    freopen("C:\\Users\\Iris\\source\\repos\\ACM\\ACM\\output.txt", "w", stdout);

#endif // LOCAL_DEBUG

    int T;

    base[] = ;

    for (int i = ; i < ; i++)base[i] = base[i - ] * ;

    int n;

    for (int ti = ;cin>>n && n; ti++) {

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

            cin >> a[i];

        }

        sort(a, a + n, cmp);

        for (int i = n - ; i >= ;i--) {

            cout << a[i];

        }

        cout << endl;

    }

    return ;

}