Lost in a Grid

Zucky wants to find his way out of a maze in minimum possible steps. Zucky knows that he can get lost in the maze if he can't find the exit so he decides to find a way by writing the code first. Now, he knows that there are doors, keys and walls in the maze. Doors and keys can be of four colors Red, Blue, Green, Yellow (RBGY) and red, blue, green, yellow (rbgy) respectively. (Capital letters repre