my code for that problem is working on custom test of cf and even in my system compiler.. and i'm getting required answer to all test cases but on submission at cf I got strange massage saying wrong answer... And that comment is

Can't find file K:\ramdisk\codeforces61\9c5383c0192771e8d22775984f40362f\check-e068a9b89c80e5d690845be2e470a589\run\output.txt invokerId=ef4de2e8346ee1a664bb563100318fea, location=203279215

plz help me to get rid of this..