#include <bits/stdc++.h>
using namespace std;
int main()
{
int t;
cin>>t;
while(t--)
{
int n;
cin>>n;
string a[n];
for(int i=0;i<n;i++)
{
cin>>a[i];
}
int counter[10];
for(int i=0;i<10;i++) counter[i] = 0;
for(int i=0;i<n;i++)
{
for(int j=0;j<a[i].length();j++)
counter[a[i][j]-48]++;
}
bool zeroDone = false;
bool nonZeroStarted = false;
for(int i=1;i<=9;i++)
{
int x= counter[i];
while(x--)
{
nonZeroStarted = true;
cout<<i;
if(nonZeroStarted && !zeroDone)
{
zeroDone = true;
int x= counter[0];
while(x--)
{
cout<<0;
}
}
}
}
cout<<endl;
for(int i=9;i>=0;--i)
{
int x=counter[i];
while(x)
{
cout<<i;
x--;
}
}
cout<<endl;
}
}
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