#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
int main(void)
{
    string str;
    vector<string> v;
    ifstream in("input.txt");
    while(in >> str)
        v.push_back(str);
    sort(v.begin(), v.end(), [](const string& l, const string& r){
        return l+r > r+l;
    });
    in.close();
    ofstream out("output.txt");
    for(auto str : v)
        out << str;
    out << endl;
    out.close();
    return 0;
}

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
inline bool cmp(const string& l, const string& r)
{
    return l+r > r+l;
}
int main(void)
{
    size_t n;
    cin >> n;
    string str;
    vector<string> v(n);
    while(n--)
    {
        cin >> str;
        v.push_back(str);
    }
    sort(v.begin(), v.end(), cmp);
    for(size_t i = 0; i < v.size(); ++i)
        cout << v[i];
    cout << endl;
    return 0;
}

for(size_t i = 0; i < n; ++i)
    cin >> v[i];