Please, give me a hint about this test

This test helped me passed 7 test. Hope, it will help you too:
2
combo
cobra

Answer is 0.

And this is just good test:
2
cooa
combo

The answer is 0.
GOOD LUCK!

Thanks, my friend) AC at last)) I should be more attentive)

Edited by author 21.08.2007 17:06

2
aaa
cabaa
One more test. answer is 2.
But it didn't helped me :(