PROGRAMMING:Finding the area of a circle
Find the area of a circle. PI is defined as 3.14159.
###Input format:
Enter several radii R
###Output format:
The circle area corresponding to each radius is output line by line, and the result retains 3 decimal places.
###Input example:
```in
one
```
###Output example:
```out
three point one four two
```
answer：If there is no answer, please comment
###Input format:
Enter several radii R
###Output format:
The circle area corresponding to each radius is output line by line, and the result retains 3 decimal places.
###Input example:
```in
one
```
###Output example:
```out
three point one four two
```
answer：If there is no answer, please comment