#include<bits/stdc++.h>
using namespace std;

bool cmp(const string& a, const string &b){
    return a+b>b+a;
    }
int main(){
    if(fopen("BAI2.INP","r")){
        freopen("BAI2.INP","r",stdin);
        freopen("BAI2.OUT","w",stdout);
    }
    int n;
    cin >> n;
    vector<string> a(n);
    for(int i = 0;i < n;i++){
        cin >> a[i];
    }
    string res = "";
    sort(a.begin(),a.end(),cmp);

    for(const string& num : a){
        res += num;
    }
    cout << res;
    return 0;
}