package main

import (
	"fmt"
	"sort"
)

func main() {
	var H, W int
	fmt.Scan(&H, &W)
	G := make([]int, H*W)
	for i := range G {
		fmt.Scan(&G[i])
	}
	sort.Ints(G)
	for i := 0; i < H; i++ {
		for j := 0; j < W; j++ {
			if j > 0 {
				fmt.Print(" ")
			}
			fmt.Print(G[i*W+j])
		}
		fmt.Println()
	}
}