import java.util.Scanner;
public class StudentID {
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        System.out.print("What is your student number? ");
        String studentNumber = scan.next();
        int numberLength = studentNumber.length();
        if(numberLength == 6)
        {
            int integerStudentNumber = Integer.parseInt(studentNumber);

            int seventhDigit = 0;
            for(int i = 6; i>= 1;i--){
               int oneNumber = integerStudentNumber % 10;
               seventhDigit = i * oneNumber + seventhDigit;

               integerStudentNumber = integerStudentNumber / 10;
            }
            System.out.println("The seventh digit is: "+ seventhDigit%10);

        }

        if(numberLength == 7)
        {
            String firstSix = studentNumber.substring(0, 6);

            String lastOne = studentNumber.substring(6);


            int firstSixStudentNumber = Integer.parseInt(firstSix);

            int lastOneStudentNumber = Integer.parseInt(lastOne);


            int seventhDigit = 0;
            for(int i = 6; i>= 1;i--)
            {
                int oneNumber = firstSixStudentNumber % 10;
                seventhDigit = i * oneNumber + seventhDigit;

                firstSixStudentNumber = firstSixStudentNumber / 10;
            }

            if(seventhDigit%10 == lastOneStudentNumber)
            {
                System.out.print("The student number is correct");
            }
            else{
                System.out.print("Student number is incorrect");
            }

        }

        }
    }