# Problem C

Ninety-One

Letâ€™s say you want to write a function that takes a single parameter $n$ and, if $n$ is greater than 100, returns $n$ minus 10, and 91 otherwise. Besides being a somewhat pointless function, it would also be trivial to implement:

if n > 100 then return n - 10 else return 91 end if

It turns out there is recursive function, called the
*McCarthy 91 function*, that behaves the same way but
which requires multiple recursive calls to produce the final
result. The function is defined thusly:

Even though this function may seem pointless, its complex recursive pattern makes it a useful test case for programming languages and formal proof systems.

**Your solution must use a
RECURSIVE function, using the definition presented
above.**

**On the exam, any other type of
solution will receive zero points!**

**EVEN IF KATTIS JUDGES IT AS
CORRECT!**

## Input

The input contains a single positive integer: $n$.

## Output

The output is the value of $M(n)$

Sample Input 1 | Sample Output 1 |
---|---|

1000 |
990 |

Sample Input 2 | Sample Output 2 |
---|---|

20 |
91 |

Sample Input 3 | Sample Output 3 |
---|---|

1 |
91 |

Sample Input 4 | Sample Output 4 |
---|---|

1872681 |
1872671 |