class A(object):
	def __init__(self, x,y,z):
		self._x = x
		self._y = y
		self._z = z

	def __str__(self):
		return "%s - %s - %s" %(self._x,self._y, self._z)

class B(A):
	def __init__(self, x,y,z, c, d):
		self._c = c
		self._d = d
		A.__init__(x, y, z)

	def __str__(self):
		return "%s - %s - %s" %(self._x,self._y, self._z)