I wanted to know, if a man was to go from $(0,0)$ to $(46,46)$ moving only straight and up with the following constraints:-

1. If he walks right, he will walk atleast $4$ consecutive coordinates.
2. If he moves up, he will walk atleast $12 $ consecutive coordinates.

How many coordinates are unreachable by him in this $46 \times 46$ grid? (Assumption:A coordinate is reachable by the man if he runs through the coordinate.)

Any help is appreciated. Thanks.