#include <bits/stdc++.h>
#define ll long long
using namespace std;
void solve(){
	ll n;
	cin>>n;
	ll countarray[10]={0};
	for(int i=0;i<n;i++){
		string s;
		cin>>s;
		for(int j=0;j<s.length();j++)
			countarray[s[j]-'0']++;
	}
	bool zero=false;
	for(int i=1;i<=9;i++){
		ll o=countarray[i];
		while(o){
			cout<<i;
			o--;
			if(!zero){
				zero=true;
				ll z=countarray[0];
				while(z){
					cout<<0;
					z--;
				}
			}
		}
	}
	cout<<endl;
	for(int i=9;i>=0;i--){
		ll o=countarray[i];
		while(o){
			cout<<i;
			o--;
		}
	}
	cout<<endl;
}
int main()
{
	ll t=1;
	cin>>t;
	while(t--){
		solve();
	}
	return 0;
}

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