#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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