I need help in my assignment,

i get stuck in half way.

Here is the question:

Pythagorean Triples

Some right triangles have sides that are all integers. A set of three integer values for the sides of a right triangle is called a Pythagorean triple. These three sides must satisfy the relationship that the sum of the squares of the two sides is equal to the square of the hypotenuse. Write a program to find all Pythagorean triples for side1, side2, and hypotenuse none larger than 30. Use a triple tested For/Next loop that tries all possibilities. This is an example of “brute force” computing. You will learn in more advanced computer science courses that there are some problems for which there is no known algorithmic approach other than using sheer brute force. .

I having trouble of Calculation , and i want show that is error message if the user key in alphabet.

Thanks!!