#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int num[21];

string nn[21];

string stri(int n)
{
    string a="";
    do
    {
        a = char(n%10 + '0') + a;
        n /= 10;
    }while(n > 0);
    return a;
}

int main()
{
    int n;
    cin >> n;
    for(int i = 1;i <= n;i++)
    {
        cin >> num[i];
        nn[i] = stri(num[i]);
        //cout << nn[i] << endl;
    }
    //cout << (nn[1] > nn[2]) << endl;
    for(int i = 1;i <= n;i++)
    {
        for(int j = i+1;j <= n;j++)
        {
            if(nn[j] > nn[i] && !(nn[j][0] == nn[i][0] && nn[i].size() == 1)){swap(nn[j],nn[i]);}
        }
    }
    for(int i =1;i <= n;i++)
    {
        cout << nn[i];
    }
    cout << endl;
    
    return 0;
}

样例什么的都可以过，但是就是75分qwq