package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
	"sort"
	"strconv"
)

const MaxInt = math.MaxInt64

var scanner *bufio.Scanner

func main() {
	h, w := Int(), Int()
	a := make([]int, h*w)
	for i := 0; i < h*w; i++ {
		a[i] = Int()
	}
	sort.Ints(a)
	for i := 0; i < h; i++ {
		sp := " "
		for j := 0; j < w; j++ {
			if j == w-1 {
				sp = "\n"
			}
			fmt.Printf("%d%s", a[w*i+j], sp)
		}
	}
}

func init() {
	scanner = bufio.NewScanner(os.Stdin)
	scanner.Buffer([]byte{}, MaxInt)
	scanner.Split(bufio.ScanWords)
}

func Int() int {
	scanner.Scan()
	ret, _ := strconv.ParseInt(scanner.Text(), 10, 0)
	return int(ret)
}

func Ints(n int) []int {
	ret := make([]int, n)
	for i := 0; i < n; i++ {
		ret[i] = Int()
	}
	return ret
}

func Max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

func Min(a, b int) int {
	if a < b {
		return a
	}
	return b
}