PROGRAMMING:Grade management
The school carries out grade management, cancels the score system, and changes it to grade evaluation. The specific method is: less than 60 is divided into e class; 60 to 70 points (excluding 70 points) were classified as D; 70 to 80 points (excluding) were classified as C; 80 to 90 points (excluding) were classified as class B; 90 or above is a. Design a program to divide the input score equivalently
###Input format:
Enter an integer to represent the grade.
###Output format:
Output the corresponding grade (capital letter) according to the input grade
###Input example:
Here is a set of inputs. For example:
```in
seventy-two
```
###Output example:
The corresponding output is given here. For example:
```out
C
```
answer：If there is no answer, please comment
###Input format:
Enter an integer to represent the grade.
###Output format:
Output the corresponding grade (capital letter) according to the input grade
###Input example:
Here is a set of inputs. For example:
```in
seventy-two
```
###Output example:
The corresponding output is given here. For example:
```out
C
```
answer：If there is no answer, please comment