Triangle Kind By Sides

Read three side lengths and classify the triangle they make. When any two sides add up to no more than the third print Not a triangle; otherwise print Equilateral when all three sides are equal, Isosceles when exactly two are equal, and Scalene when none are. Input: three lines, each a positive integer, no prompts. Output: one line. Order the chain so the validity test comes first and the most specific shape before the less specific one.