Consider the following recursive algorithm:

int f$($n$)$

$/*$ n is an integer greater than equal to $1*/$

$\{$

Let cba be the last three digits of your CWID; $/*$ e$.$g$.,$ my CWID ends with $651$; c$=6,$ b$=5$; a$=1*/$

if $($n$==1)$ return a;

if $($n$==2)$ return b;

if $($n$==3)$ return c;

int x $=$ f$($n$-3)$;

if $($x is even$)$ x $=$ x $+$ f$($n$-2)$ ;

if $($x is odd$)$ x $=$ x $+$ f$($n$-1)$ ;

return x ;

$\}$;

Draw the recursion tree for f$(7).$ In this tree, draw all subtrees even though some of them may be identical. Show the returned values for each recursive call. In particular, what is the value returned for f$(7)?($ zero $($i$.$e$.,0)$ is an even number $)$