how to make program that keeps score and loops till XXX is inputed

hi can some1 pls help me out im trying to make a program that loops till you type in xxx. i got that part done but the main goal of the program is that you need to type in a word and then the following word's first letter should start with the previous word's last letter for e.g. input:hello input:over input:rare input:xxx
output:score:3
if the word doesnt start with the previous word last letter it is counted as incorrect and if it starts with the last letter it is correct
later on the score = correct - incorect to get score here is my code pls help me out im strugling bad with this program

here is code

Code:

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String bgnword = JOptionPane.showInputDialog("Enter a begin word: ");
        int score;
        int len = bgnword.length();
        score = 0;
        String word;
        int corwrd = 0;
        int incwrd = 0;
        String prevword = null;
        while(!"XXX".equals(word = JOptionPane.showInputDialog("Enter a word or XXX to quit.")))
        {
            char bgn = bgnword.charAt(len - 1);
           
           
            prevword = word;
           
            int len2 = word.length();
            char ch1 = word.charAt(0);       
            char ch2 = prevword.charAt(len2 - 1);
            if (prevword != null)
            {
                if(ch1 == ch2)
                {
                    corwrd++;
                }
                else
                {
                    incwrd--;
                }
                score = corwrd - incwrd;
               
            }
        }
                   
        System.out.println("Score: " + score);

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can any1 pls help me on this 1

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