Sum of Digits

Description:

Input:

The first line contains the only integer n (0 ≤ n ≤ 10¹⁰⁰⁰⁰⁰). It is guaranteed that n doesn't contain any leading zeroes.

Output:

Print the number of times a number can be replaced by the sum of its digits until it only contains one digit.

Sample Input:

0

Sample Output:

0

Sample Input:

10

Sample Output:

1

Sample Input:

991

Sample Output:

3

Note:

In the first sample the number already is one-digit — Herald can't cast a spell.

The second test contains number 10. After one casting of a spell it becomes 1, and here the process is completed. Thus, Gerald can only cast the spell once.

The third test contains number 991. As one casts a spell the following transformations take place: 991 → 19 → 10 → 1. After three transformations the number becomes one-digit.