Given the function

void f$($n$,$ m$)$:

input: two integers n$,$ m$,$ both of which are in form of $2$

p

i $1$;

j $$ m;

k $0$;

while i $<$ n:

i $$ i $*2$;

k $$ k $+$ i;

while j $>1$:

j $$ j $/2$;

k $$ k $+$ j;

return k;

a$.$ Calculate the value of k$.$

b$.$ Compute the computational complexity of the function and express your result using Big$-$Oh

notation.