# [Thunno](https://github.com/Thunno/Thunno), \$ 9\log_{256}(96)\approx \$ 7.41 bytes
```
D2%s1-z*S
````
[Attempt This Online!](https://ato.pxeger.com/run?1=m72sJKM0Ly9_wYKlpSVpuhYrXYxUiw11q7SCIXyo8IJl0cY6CqaxEB4A)
Port of Jonathan Allan's Jelly answer.
#### Explanation
```python
D2%s1-z*S # Implicit input
D2% # Duplicate and mod by 2
s1- # Swap and subtract one
z* # Multiply
S # Sum