Student Grade Classifier

Read n lines name,marks. Print name:grade (A>=90, B>=75, C>=60, D>=40, F). Print average.

Your task

Write a complete program: read the input with input() and print the result with print().

Example

Input

3
Alice,95
Bob,72
Charlie,58

Output

Alice: A
Bob: C
Charlie: D
Average: 75.00