Competitions

# Math functions

# f91

McCarthy is a famous theorician of computer science. In his work, he defined a recursive function, called **f91**, that takes as input a positive integer **n** and returns a positive integer defined as follows:

If **n** ≤ **100**, then **f91**(**n**) =** f91**(**f91**(**n** + **11**));

If **n** ≥ **101**, then **f91**(**n**) = **n** - **10**.

**Input**

A positive integer **n** not greater than **1000000**.

**Output**

The value of **f91**(**n**).

Input example #1

91

Output example #1

91