def thirdAngle(ang1, ang2):
    if ang1 == 0:
        raise("Angle can't be 0")
    if ang2 == 0:
        raise("Angle can't be 0")
    ang3 = 180-(ang1+ang2)
    if ang3 > 0:
        return ang3
    else:
        raise Exception("Sum of angles must be 180")