Let's define digit degree of some positive integer as the number of times we need to replace this number with the sum of its digits until we get to a one digit number.

Given an integer, find its digit degree.

Example

• For n = 5, the output should be digitDegree(n) = 0;
• For n = 100, the output should be digitDegree(n) = 1. 1 + 0 + 0 = 1.
• For n = 91, the output should be digitDegree(n) = 2. 9 + 1 = 10 -> 1 + 0 = 1.

Hints

• toString()
• parseInt()
• split()
• reduce()

Input/Output

• [time limit] 4000ms (js)

• [input] integer n

Guaranteed constraints:

5 ≤ n ≤ 109.

• [output] integer