Consider the same operation$-$counting rules and Python program we saw in the last video's question:

Each addition and subtraction costs $1$

Each comparison $($a $>$ b$)$ costs $1$

Everything else is free

$7$

def fun$($n$,$x$)$:

counter $=$ n

amount $=0$

while counter $>0$:

amount $=$ amount $+$ x

counter $=$ counter $-1$

return amount

As we saw before, the cost of calling this function, by the above rules, is $3$n $+1.$

What is the smallest expression g such that the cost of calling the function is O$($g$)?$