#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;

int n, now_max;
char num[1005][205];
bool out[1005];
string ans;

bool cmp(char a[], char b[]) {
	int lena = strlen(a);
	int lenb = strlen(b);
	if (lena > lenb) return true;
	else if (lena < lenb) return false;
	for (int i = 0; i < lena; i++) {
		if (a[i] > b[i]) return true;
		else if (a[i] < b[i]) return false;
	}
	return true;
}

int main() {
	freopen("brick.in", "r", stdin);
	freopen("brick.out", "w", stdout);
	scanf("%d", &n);
	for (int i = 1; i <= n; i++) {
		scanf("%s", &num[i]);
	}
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			if (!out[j]) {
				now_max = j;
				break;
			}
		}
		for (int j = 1; j <= n; j++) {
			if (!out[j]) {
				if (!cmp(num[now_max], num[j])) {
					now_max = j;
				}
			}
		}
		ans += num[now_max];
		out[now_max] = true;
	}
	cout << ans << "\n";
	return 0;
}