class Vector2D:

    def __init__(self,x,y):
        self.x = x
        self.y = y

    def __add__(v1,v2):
        suma = v1.x + v2.x
        suma2 = v1.y + v2.y
        return Vector2D(suma,suma2)

    def __str__(self):
        return '(%s,%s)' % (self.x,self.y)

    def __sub__(v1,v2):
        resta = v1.x - v2.x
        resta2 = v1.y - v2.y
        return Vector2D(resta,resta2)

    def productoesc(v1,v2):
        mult = v1.x + v2.x
        mult1 = v1.y + v2.y
        mult2 = mult * mult1
        return mult2


v1 = Vector2D(3,10)
v2 = Vector2D(6,8)

print v1+v2
print v1-v2
print productoesc(v1,v2)