For mov$/$add$/$sub instructions in AL$,$ both operands cannot be memory operands $($variables$)$ at the same time. For example, suppose a and $b$ are variables, then none of the following AL instruction is invalid:

mov $a,b$

add $a,b$

sub $a,b$

$(1)$ Write an AL program to implement the following Java expressions $($do not make any change to the following expressions and your AL program should be exactly equivalent to the following expressions$)$:

int $a=6,b=4,c=3$;

int $x=a+(b-c)$;

Note that int in Java takes $4$ bytes.