#include <iostream>
#include <algorithm>
using namespace std;
const int N = 105;
void *memset(void *str, int c, size_t n);
int arr[N][N];
struct point{

		int p_x,p_y;
	    int value;
}p[N*N];
bool com(point j,point k);
int main(){
	int i,m,n,a=0;
	memset(arr,0,sizeof arr);
	cin>>i;
	for(;i>0;i--){
		cin>>n>>m;
	for(int x=1;x<=n;x++)
		for(int q=1;q<=m;q++){
			p[++a].p_x = x;
			p[a].p_y = q;
			cin>>p[a].value;}
		sort(p+1,p+1+a,com);
	for(int q=1;q<=m;q++)
	arr[p[q].p_x][q] = p[q].value;
	for(int x=m+1;x<=a;x++)
		for(int q=1;q<=m;q++){
	if(	arr[p[x].p_x][q] == 0){
						arr[p[x].p_x][q]=p[x].value;
						break;
				}}
	for(int x=1;x<=n;x++){
		for(int q=1;q<=m;q++){
		cout<<arr[x][q]<<' ';}
			cout<<endl;}
				}
	return 0;
}
            bool com(point j,point k){
		return j.value<k.value;}