MINIMAX problem corner cases??

Code MINIMAX :- I have tried many test cases of my own and its passing all of them !I dont know why a wrong answer is coming !
Here is the code:-
Algorith is straight forward calculate max(min(all rows))=max,min(max(all columns))=min and calculate first occurance of both and then start counting the number of changes in all rows and columns and Display the minimum answer!!

Can anybody provide me with corner cases of this problem?