public void calculateFactorial(int number) {
     if (number < 0 || number > 70) {
         System.out.println("Invalid number.");
     }
    if (number < 70 && number > 0) {
         long num = (long) (number);
         long factorial = 1;
         
         for(int i = 1; i < number; i++) {
            if(i == 1) {
                factorial = num * (num - i);
            } else {
                factorial *= num - i;
            }
        }


        System.out.println("The factorial is: " + factorial);
   }

}