PROGRAMMING:Piecewise function 3

Input integer x, calculate y and output. The formula is as follows:
###Input format:
Enter an integer directly without any additional characters.
###Output format:
Output according to the format sequence of "y = result", where the result is the original output of 6 decimal places, without any additional format control.
###Input example:
```in
five
```
###Output example:
```out
y=8.000000
```
###Input example:
```
-2
```
###Output example:
```
y=-1.000000
```






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