#include<math.h>
#include<algorithm>
#include<cstring>
#include<stdio.h>
#include<iostream>
#include<stack>
#include<queue>
#include<cstring>
using namespace std;
int a[25];
bool cmp(char a,char b){
	return a>b;
} 
int main(){
	int n;
	cin>>n;
	for(int i=0;i<=n-1;i++){
		cin>>a[i];
	}
	sort(a,a+n,cmp);
	for(int i=0;i<=n-1;i++){
		printf("%d",a[i]);
	}
	return 0;
}