The Fibonacci sequence $1,1,2,3,5,8,13,21......$ starts with two $1$s$,$ and each term afterwards is the sum of its two predecessors. Please write a function, Fib$($n$),$ which takes n as the input parameter. It will return the n$-$th number in the Fibonacci sequence.

Testing commands: Fib$(1)$; Fib$(2)$; Fib$(100)$

$1.$ Use loop

$2.$ Use recursion