PROGRAMMING:Grade conversion
Enter the percentile score, enter the five level system, a, B, C, D, e. 90 points and above belong to a, 80 points and above belong to B, 70 points and above belong to C, 60 points and above belong to D, 60 points and below belong to E.
###Input format:
A score of n.
###Output format:
Which grade does this grade belong to.
###Input example:
Here is a set of inputs. For example:
```in
eighty-eight
```
###Output example:
The corresponding output is given here. For example:
```out
B
```
answer：If there is no answer, please comment
###Input format:
A score of n.
###Output format:
Which grade does this grade belong to.
###Input example:
Here is a set of inputs. For example:
```in
eighty-eight
```
###Output example:
The corresponding output is given here. For example:
```out
B
```
answer：If there is no answer, please comment