using System.Collections.Generic;
using System;

public class Hello
{
    public static int h, w;
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        h = int.Parse(line[0]);
        w = int.Parse(line[1]);
        var t = new List<int>();
        for (int i = 0; i < h; i++)
        {
            line = Console.ReadLine().Trim().Split(' ');
            for (int j = 0; j < w; j++) t.Add(int.Parse(line[j]));
        }
        getAns(t);
    }
    static void getAns(List<int> t)
    {
        t.Sort();
        var p = 0;
        var res = new int[w];
        for (int i = 0; i < h; i++)
        {
            for (int j = 0; j < w; j++) res[j] = t[j + p];
            Console.WriteLine(string.Join(" ", res));
            p += w;
        }
    }
}