15650.java

import java.io.*;
import java.util.*;

public class Main {

    public static int[] arr;
    public static boolean[] visited;
    public static StringBuilder sb = new StringBuilder();

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());

        int N = Integer.parseInt(st.nextToken());
        int M = Integer.parseInt(st.nextToken());

        arr = new int[M];
        visited = new boolean[N];
        dfs(N, M,0);
        System.out.println(sb);

    }

    public static void dfs(int N, int M, int depth) {
        if (depth == M) {
            for (int val : arr) {
                sb.append(val).append(' ');
            }
            sb.append('\n');
            return;
        }

        for (int i = 0; i < N; i++) {
            if (!visited[i]) {
                if (depth == 0){
                    visited[i] = true;
                    arr[depth] = i + 1;
                    dfs(N, M, depth + 1);
                    visited[i] = false;
                }
                else if (depth > 0 && i > arr[depth - 1] - 1){
                    visited[i] = true;
                    arr[depth] = i + 1;
                    dfs(N, M, depth + 1);
                    visited[i] = false;
                }
            }
        }
    }

}