Scanner scan = new Scanner (System.in);
    String text;
    int langd;
    int nisse = 0;
    System.out.print("Skriv in text: ");
    text = scan.nextLine();
    langd = text.length();
    
    for (int i = 0; i < langd; i++){
        if(text.substring(i,i+1).equals("a")){
        nisse += 1;
        }
    }
    System.out.print(nisse);