Having watched the last Harry Potter film, little Gerald also decided to practice magic. He found in his father's magical book a spell that turns any number in the sum of its digits. At the moment Gerald learned that, he came across a number n. How many times can Gerald put a spell on it until the number becomes one-digit?
The first line contains the only integer n (0≤n≤10100000). It is guaranteed that n doesn't contain any leading zeroes.
Print the number of times a number can be replaced by the sum of its digits until it only contains one digit.
0
0
10
1
991
3
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.