I was trying to submit this problem after ensuring the 4 test cases given in the problem, but I found it gives wrong answer in test 4. however, this test case I try it, and I'm sure my program output the correct answer

My submission

in the fourth test case

10 10

10 10

10 10

the answer is -1 and my program actually output -1, but in the submission it said my output is :

8 2

2 0

could anyone explain why !!