import java.util.Scanner;

public class Main{
	
	public static void main(String[] args) {
			
		Scanner sc = new Scanner(System.in);
		System.out.print("Please enter the number of students : ");
		int ogrenci_sayisi=sc.nextInt();
		
		int[] array_1 = new int[ogrenci_sayisi];
		for (int i = 0; i < ogrenci_sayisi; i++) {
			System.out.print("please enter the student nots : ");
			array_1[i]=sc.nextInt();
		}
		
		char[] array_2 = new char[ogrenci_sayisi];
		float avarage_grade=0;
		int grade_a=0;
		int grade_b=0;
		int grade_c=0;
		int grade_d=0;
		int grade_e=0;
		int grade_f=0;

		for(int k =0;k<ogrenci_sayisi;k++) {
			if(array_1[k]>=90) {
				array_2[k]='A';
			}
			else if(array_1[k]>=80) {
				array_2[k]='B';
			}
			else if(array_1[k]>=70) {
				array_2[k]='C';
			}
			else if(array_1[k]>=60) {
				array_2[k]='D';
			}
			else if(array_1[k]<=60) {
				array_2[k]='E';
			}
			//
			avarage_grade+= array_1[k];
			if(array_2[k]=='A') {
				grade_a++;
			}
			else if(array_2[k]=='B') {
				grade_b++;
			}
			else if(array_2[k]=='C') {
				grade_c++;
			}
			else if(array_2[k]=='D') {
				grade_d++;
			}
			else if(array_2[k]=='E') {
				grade_e++;
			}
			
		}
		if(grade_a==0) {
			System.out.println("Noone of the students has grade A");
		}
		else if(grade_b==0) {
			System.out.println("Noone of the students has grade B");
		}
		else if(grade_c==0) {
			System.out.println("Noone of the students has grade C");
		}
		else if(grade_d==0) {
			System.out.println("Noone of the students has grade D");
		}
		else if(grade_e==0) {
			System.out.println("Noone of the students has grade E");
		}
		else if(grade_f==0) {
			System.out.println("Noone of the students has grade F");
		}
		avarage_grade=avarage_grade/ogrenci_sayisi;
		
		System.out.println("Ortalama: "+avarage_grade);
		
		System.out.println("A alanlar : "+grade_a);
		System.out.println("B alanlar : "+grade_b);
		System.out.println("C alanlar : "+grade_c);
		System.out.println("D alanlar : "+grade_d);
		System.out.println("E alanlar : "+grade_e);

		


		
	}
	
	
}