#420. Digit sum steps
You get n. How many times do you replace n by the sum of its digits until it has one digit?
### Input
One integer n (0 ≤ n ≤ 10¹⁸).
### Output
The number of steps.
Examples
Input
850148570738625015
Output
3
Input
797019584774633370
Output
2
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.