Write a Java program to create and display unique three-digit number using 1, 2, 3, 4. Also count how many three-digit numbers are there

import java.util.Scanner;

public class Exercise39 {
    
 public static void main(String[] args) {
		int amount = 0;
		for(int i = 1; i <= 4; i++){
			for(int j = 1; j <= 4; j++){
				for(int k = 1; k <= 4; k++){
					if(k != i && k != j && i != j){
						amount++;
						System.out.println(i + "" + j + "" + k);
					}
				}
			}
		}
		System.out.println("Total number of the three-digit-number is " + amount);
	}
}

Sample Output:

123                                                                                                      
124                                                                                                      
132                                                                                                      
134                                                                                                      
142                                                                                                      
143                                                                                                      
213                                                                                                      
214                                                                                                      
231                                                                                                      
234                                                                                                      
241  
------
431                                                                                                      
432                                                                                                      
Total number of the three-digit-number is 24