Problem Statement:
Prana has given a number. Now she wonder what will be the maximum number of digits that the sum of these digits is equals to the given number. After thinking sometimes she laughed at herself, cause the number is infinite.

Now your task is to find the minimum number of digits that the sum of these digits is equals to the given number.
Input:
The input contain a single integer N ( 0 ≤  N ≤ 1031 ). The input is terminated by a line containing -1.
Output:
Output a single line the number of digits that the sum of the digits is equals to the given number. See the sample input/output for exact formatting.
Sample Input/Output:
Sample Input
Sample Output
 11
 1
 -1
 2
 1

Explanation :
For the first test case given number is 11. Some possible way to make 11 is

7+4=11 which costs 2 digits.

2+3+6=11 which costs 3 digits.

1+2+3+5=11 which costs 4 digits.

1+2+3+0+5=11 which costs 5 digits.


So, here first example costs the minimum number of digits which is 2.
Note: There are no extra new lines between different numbers.
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Problem setter: Abu Sufian, Dept. of CSE
Bangladesh University of Business and Technology (BUBT)