Help me in solving SEMCOURSES problem

My issue

how to find the logic

My code

/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;

/* Name of the class has to be "Main" only if the class is public. */
class Codechef
	public static void main (String[] args) throws java.lang.Exception
		// your code goes here

Problem Link: SEMCOURSES Problem - CodeChef

The logic is the ans would be X * Y * Z.