McCarthy 91 function

The McCarthy 91 function is a recursive function defined as follows: \[ M(n) = \begin{cases} n - 10 & \text{if } n > 100 \\ 91 & \text{if } n \leq 100 \end{cases} \] This means: - If \( n \) is greater than 100, the function returns \( n - 10 \).