Jafar has managed to trick Aladdin into his evil and vicious plan of obtaining the power of the Genie by sending him inside the Cave of Wonders. Unaware of Jafar's plan, Aladdin promises to bring him the magic lamp. To get the magic lamp the Cave of Wonders or Tiger's Cave test the intelligence of the person that enters in it. Going further into the cave Aladdin finds himself surrounded by various challenges from time to time. Let’s see whether Aladdin survives the cave's test or not.Aladdin is searching for the lamp and during his search, he comes across a door guard- ed by a spirit. In order to get past the door, the spirit challenged Aladdin in a game of chess. The chessboard being old is broken into 4 pieces each of size 3 by 3. Apart from that, some squares are of the wrong colour with j-th square of the i -th row of k-th piece of the board has colour ak,i,j . The spirit wants Aladdin to change the colour of some squares in such a way that he recolours the minimum number of squares and the obtained pieces form a valid chessboard. Every square has a different colour from each of the neighbouring side by side squares in a valid board. Its size should be 6 by 6. Aladdin can move the pieces but he cannot rotate and flip them. What is the minimum number of colours Aladdin should recolour to obtain a valid chessboard and get past the door?