Consider a method printTriangleType that accepts three integer arguments representing the lengths of the sides of a triangle and prints the type of triangle that these sides form. The three types are equilateral, isosceles, and scalene. An equilateral triangle has three sides of the same length, an isosceles triangle has two sides that are the same length, and a scalene triangle has three sides of different lengths.

However, certain integer values (or combinations of values) would be illegal and could not represent the sides of an actual triangle. What are these values? How would you describe the precondition(s) of the printTriangleType method?