Having Trouble with Correct output from If statement

I could use some help with an assignment. The user has to enter the number of students and then enter scores and I have to find the best score and assign a grade accordingly.

Grade is A if score is >= best-10

Grade is B if score is >= best-20

Grade is C if score is >= best-30

Grade is D if score is >= best-40

Grade is F otherwise

My program is not producing the correct grades at the moment and I tried putting another for loop right before my if but nothing changed and then I tried using another variable (j instead of i) but I'm sort of stuck. I'm new to java so any help would be appreciated, and thank you in advance :)

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          import java.util.Scanner;
          public class Main
            {
         public static void main(String[] args) {
           Scanner input = new Scanner(System.in);
           System.out.print("Enter the number of students: ");
           int students = input.nextInt();

            int[] grades = new int [students];


            System.out.print("Enter " + students + " scores: ");
            for(int i=0; i<students; i++){
              grades[i] = input.nextInt();
          }

           int max = grades[0];
           for(int i = 0; i<grades.length; i++){

            if(grades[i] > max){
                max = grades[i];
            }

           for(i = 0; i<grades.length; i++){
             if (grades [i] >= max-10){
                 System.out.println("Student " + i + " score is: A");
              }else if (grades[i] >= max-20){
                 System.out.println("Student " + i + " grade is: B");
              }else if (grades [i] >= max-30){
                 System.out.println("Student " + i + " grade is: C");
              }else if (grades[i] >= max-40){
                 System.out.println("Student " + i + " grade is: D");
              }else{
                 System.out.println("Student " + i + " grade is: F");
              }
             }
            }
            }
           }
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