#140EasyConditionals· Combining Conditions

Triangle Classifier

Write `classify_triangle(a, b, c)` that classifies three side lengths: - `"invalid"` if any side is 0 or negative, or if one side is greater than or equal to the sum of the other two (the sides cannot meet). - `"equilateral"` if all three sides are equal. - `"isosceles"` if exactly two sides are equal. - `"scalene"` if all sides are different.

Input format

`a`, `b`, `c`: integers.

Output format

One of `"invalid"`, `"equilateral"`, `"isosceles"`, `"scalene"`.

Examples

Input: a = 3, b = 4, c = 5

Output: "scalene"

All different, and every side is shorter than the other two together.

Input: a = 1, b = 2, c = 3

Output: "invalid"

1 + 2 is not greater than 3: the sides would lie flat.

Constraints

-1000 <= a, b, c <= 1000

Study first

Conditionals: if, elif and else

#python
#conditionals
#logical-operators
#geometry