Why does it always print F in my else-if statement

I’m a beginner at java, So my goal was to determine the average of 3 user inputted scores using multiple classes and print whether if it is 60>n = F, 70>n = D 80>n = C, 90>n = B, 100>n = A, and 101>n = ? where n is the value of the 3 scores that was averaged. 1st class having the scanners and second class having the else-if, the inputted data and the computed average of them.

import java.util.Scanner;
public class MyClass {
    public static void main(String args[]) {
        Scanner myObj = new Scanner(System.in);
        
        System.out.println("Enter your Score on HTML: ");
        double Score1=myObj.nextDouble();
        System.out.println("Enter your Score on JAVA: ");
        double Score2=myObj.nextDouble();
        System.out.println("Enter your Score on C: ");
        double Score3=myObj.nextDouble();
        
        System.out.println("Total average: " + Score1 + Score2 + Score3);
        Second R = new Second(Score1,Score2,Score3);
        
        R.P();
    }
}


--------------------------------------------------------------

public class Second {
    double S1;
    double S2;
    double S3;
    double average;
    Second(double Score1, double Score2, double Score3)
{
    Score1 = S1;
    Score2 = S2;
    Score3 = S3;
    average = (Score1 + Score2 + Score3) /3;
}
// public char calcAverage();
// double average (Score1, Score2, Score3)

public void P(){
    if(average < 60){
        System.out.println("F");
        
    }else if(average < 70){
        System.out.println("D");
        
    }else if(average < 80){
        System.out.println("C");
        
    }else if(average < 90){
        System.out.println("B");
        
    }else if(average < 100){
        System.out.println("A");
        
    }else {
        System.out.println("?");
    }
}
}

What I am expecting is for it to print A-F depending on the computed average but it always return F regardless of how high the value was inputted.

>Solution :

There’s an error in class Second constructor

    Second(double Score1, double Score2, double Score3)
{ 
    Score1 = S1; ### it should be S1 = Score1
    Score2 = S2; ### it should be S2 = Score2
    Score3 = S3; ### it should be S3 = Score3
    average = (Score1 + Score2 + Score3) /3;
}

because your S1,S2,S3 was initialized with zero it prints F