PROGRAMMING:Enter the radius and calculate the circle area

This topic requires input circle radius, calculate and output circle area.
###Input format:
Enter a number on a line
five
###Output format:
Output a number on a line
seventy-eight point five
###Input example:
Here is a set of inputs. For example:
```in
five
```
###Output example:
The corresponding output is given here. For example:
```out
seventy-eight point five
```







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