#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>

using namespace std;


int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int nums_amount;
    cin >> nums_amount;
    vector<string> nums(nums_amount);
    for (int i = 0; i < nums_amount; i++) {
        cin >> nums[i];
    }
    sort(nums.begin(), nums.end(), [](const string& a, const string& b) {
        return a + b < b + a;
    });
    for (int i = nums_amount - 1; i >= 0; i--) {
        cout << nums[i];
    }
    cout << " ";
    for (int i = 0; i < nums_amount; i++) {
        cout << nums[i];
    }
    cout << endl;

    return 0;
}