Let ܰN be the set of natural numbers and ݂F : N → N be defined by
\(f(x)=\left\{\begin{aligned} x / 2, & x \text { is even } \\ 3 x+1, & x \text { is odd } \end{aligned}\right.\)
Let ݂fn(x) denote the ݊-fold composition of ݂f(x). What is the smallest integer n such that fn(13) = 1 ?
Enter numerical value using the virtual keypad. Round off where necessary.