class Student extends Person{
	private int[] testScores;
    Student(String firstname,String lastname,int id,int testScores[]){
       super(firstname,lastname,id);
        this.testScores=testScores;
    }
    public char calculate(){
        int sum=0;
        for(int i=0;i<testScores.length;i++){
            sum=sum+testScores[i];
        }
        int avg=sum/testScores.length;
        if(avg>=90 && avg<=100) return 'O';
        else if(avg>=80 && avg<90) return 'E';
        else if(avg>=70 && avg<80) return 'A';
        else if(avg>=55 && avg<70) return 'P';
        else if(avg>=40 && avg<55) return 'D';
        else return 'T';
    }
}