#847. Kaprekar steps
You get a 4-digit number whose digits are not all the same. Sort its digits from biggest to smallest to make one number and from smallest to biggest to make another, then subtract the second from the first. How many times must you do this to reach 6174? (Always treat the number as 4 digits, adding 0s in front.)
### Input
One integer n (1000 ≤ n ≤ 9999).
### Output
Answer.
Examples
Input
6722
Output
5
Input
7237
Output
5
💡 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.