THREE MODULES CHECKER

 import java.util.Scanner;

public class even {
    public static void main(String[] args) {
        System.out.println("THIS SYSTEM CHECKS ANY THREE MODULES AND OUTPUT THE AVERAGE");
        System.out.println("Enter module 1");
        Scanner input = new Scanner(System.in);
        while (!input.hasNextDouble()){
            System.out.println("Enter a number not a letter");
            input.next();
        }
        int module1;
        module1  = input.nextInt();
        while (module1<0 || module1 >100){
            System.out.println("Enter a number between 1 and 100");
            while (!input.hasNextDouble()){
                System.out.println("Enter a number not a letter");
                input.next();
            }
            module1  = input.nextInt();
        }
        System.out.println("Enter module 2");
        while (!input.hasNextDouble()){
            System.out.println("Enter a number not a letter");
            input.next();
        }
        int module2;
        module2  = input.nextInt();
        while (module2<0 || module2 >100){
            System.out.println("Enter a number between 1 and 100");
            while (!input.hasNextDouble()){
                System.out.println("Enter a number not a letter");
                input.next();
            }
            module2  = input.nextInt();

        }
        System.out.println("Enter module 3");
        while (!input.hasNextDouble()){
            System.out.println("Enter a number not a letter");
            input.next();
        }
        int module3;
        module3  = input.nextInt();
        while (module3<0 || module3>100){
            System.out.println("Enter a number between 1 and 100");
            while (!input.hasNextDouble()){
                System.out.println("Enter a number not a letter");
                input.next();
            }
            module3  = input.nextInt();

        }
        int adding = module2 + module1 + module3 ;
        int average = adding/3;
        if (average>=70){
            System.out.println("A");
        } else if (average>=60 && average<=69) {
            System.out.println("B");
        } else if (average>=50 && average<=59) {
            System.out.println("C");
        } else if (average>=40 && average<=49) {
            System.out.println("C");
        } else if (average>=0 && average<=39) {
            System.out.println("F");
        }
    }
}