+import collections
+
+
+
+class YX(collections.namedtuple('YX', ('y', 'x'))):
+
+ def __add__(self, other):
+ return YX(self.y + other.y, self.x + other.x)
+
+ def __sub__(self, other):
+ return YX(self.y - other.y, self.x - other.x)
+
+ def __str__(self):
+ return 'Y:%s,X:%s' % (self.y, self.x)