Just for fun I have been trying to solve an algorithm challenge but sadly my solution fails. Here is the description of the challenge:
Input
Each test file contains three lines.

First line starts with two space-separated integers NN and MM, the size of the list and the number of words Kanga says respectively.
Second line follows, containing NN space-separated words. This composes the no-no list.
Third line contains MM space-separated words. This composes the words Kanga has said during the day.

Each word is always strictly composed of lowercase english characters (a-z).
All words in the no-no list are unique, i.e. there are no repeated words
The length of each word is at most 1010 characters long.

Output
A single line containing a number - the number of times Kanga said a word that was in the no-no list.

Example:
Sample Input:
5 12
smallest take most room in
sometimes the smallest things take up the most room in your heart

Sample Output:
5
A quick solution I came up with is the following:
Code:
import java.util.Scanner;

public class JavaApplication1 {

    public static void main(String[] args)  {
        
        Scanner myObj = new Scanner(System.in);  
        
        //System.out.print("Input N & M: ");
        String NM = myObj.nextLine();  
        
        //System.out.print("Input N: ");
        //String N = "smallest take most room in"; 
        String N = myObj.nextLine(); 
        String N2 = N.replace(" ", "XX");
        
        //System.out.print("Input M: ");
        //String M = "sometimes the smallest things take up the most room in your heart"; //myObj.nextLine(); 
        String M = myObj.nextLine(); 
        
        String[] tempArray;
 
        String delimiter = " ";
 
        tempArray = M.split(delimiter);
 
        int occurence = 0;
        for (int i = 0; i < tempArray.length; i++)
        {
            if (N2.contains(tempArray[i]))
                occurence += 1;
        }
        
         System.out.println(occurence);
    }    
}
The solution above "seems" to solve the problem but whenever I submit it it always fails. Can anyone point out where I could be failing their tests?