Competitions

# Removing Digits

You are given an integer n. On each step, you may subtract from it any one-digit number that appears in it.

How many steps are required to make the number equal to 0?

#### Input

One integer n (1n106).

#### Output

Print one integer: the minimum number of steps.

#### Explanation

An optimal solution is 2720181090.

Time limit 1 second
Memory limit 128 MiB
Input example #1
27

Output example #1
5