You are given 2 out of 3 angles in a triangle, in degrees.
Write a function that classifies the missing angle as either "acute", "right", or "obtuse" based on its degrees.
For example: missing_angle(11, 20) should return "obtuse", since the missing angle would be 149 degrees, which makes it obtuse.
missing_angle(27, 59) ➞ "obtuse"
missing_angle(135, 11) ➞ "acute"
missing_angle(45, 45) ➞ "right"
The sum of angles of any triangle is always 180 degrees.