PROGRAMMING:Finding the circumference of a circle
Input the radius r of the circle, calculate its perimeter and output, and the PI is defined as 3.14159.
###Input format:
Enter the integer radius R.
###Output format:
Output the circle length s obtained according to the radius, and the result retains 2 decimal places
###Input example:
```in
twenty
```
###Output example:
The corresponding output is given here. For example:
```out
s = 125.66
```
answer：If there is no answer, please comment
###Input format:
Enter the integer radius R.
###Output format:
Output the circle length s obtained according to the radius, and the result retains 2 decimal places
###Input example:
```in
twenty
```
###Output example:
The corresponding output is given here. For example:
```out
s = 125.66
```
answer：If there is no answer, please comment