PROGRAMMING:Calculate the area of a circle
###Task description
This topic requires reading in a real number representing the radius of the circle and outputting the area of the circle. The value of PI in the program is 3.14159265.
###Input format:
Input only one line, 1 real number.
###Output format:
Output the result in one line, keeping 4 decimal places.
###Input example:
```in
one
```
###Output example:
```out
three point one four one six
```
###Tips
When outputting real data, the%. 3lf format can be used to control the output of only 3 decimal places.
answer：If there is no answer, please comment
This topic requires reading in a real number representing the radius of the circle and outputting the area of the circle. The value of PI in the program is 3.14159265.
###Input format:
Input only one line, 1 real number.
###Output format:
Output the result in one line, keeping 4 decimal places.
###Input example:
```in
one
```
###Output example:
```out
three point one four one six
```
###Tips
When outputting real data, the%. 3lf format can be used to control the output of only 3 decimal places.
answer：If there is no answer, please comment