I have a problem to solve with k nearest neighbor (kNN).

12 points are given in two dimensions, which belong to one of the two classes - and + as shown below. Which is the minimum value that k can have for the algorithm to classify correctly the point (0,0) that belongs in the class +. (Consider Manhattan distance).

1 0 -1 0 2 2 0 -2 -2 -2 0 2

0 1 0 -1 0 2 2 2 0 -2 -2 -2

- - - - + + + + + + + +

Thank you.