Write a program to evaluate the following expression.

You are to evaluate the following equation:

num1 - (input + num2) - (num3 + num4)

Input will be a hex number input by the user using Readhex. The input can be 1,2,3,4 or 5 hex digits. num1, num2, num3 and num4 are variables defined in the data section of your program.

When you evaluate the above expression you should follow the normal order of operations for evaluating a math expression. You should evaluate the expressions within the parenthesis first and then work left to right.

For example when you evaluate 7 - 3 - 2 you should work left to right so the answer is: 7 - 3 = 4 - 2 = 2. If you work from right to left you get the wrong answer: 3 - 2 = 1 and 7 - 1 = 6.

You must evaluate the above equation as it is and not simplify it. In other words you must evaluate: num1 - (input + num2) - (num3 + num4) not evaluate something like num1 - input - num2 - num3 - num4 etc.

Also do not reverse the order of the operations within the (). You must evaluate (input+num2) and (num3+num4) and not (num2+input) or (num4+num3). Later we will learn that the order of the operands is important as we write a program to evaluate any expression.