Read a positive integer n from standard input and print how many steps it takes to reach 1 using the Collatz rule: if n is even, halve it; if n is odd, replace it with 3 * n + 1. Count each transformation. For example, starting from 6 the sequence is 6, 3, 10, 5, 16, 8, 4, 2, 1, which takes 8 steps, so print:

8

Loop while n != 1, incrementing a counter each pass.