How to unroot and remove all traces of a root topic

My device is a samsung galaxy tab 3 8.0 and I need to get rid of any and all signs of a root if that means I need to flash the official stock rom where can I get it for MY model. If there is A FLASH COUNTER OR BOOTLOADER THAT NEEDS TO BE RESET than how do I do that. I NEED EVERY LITTLE TRACE OF A ROOT GONE. I AM NEW TO ANDROID SO ACT LIKE I DONT KNOW ANY THING PLEASE. I NEED TO KEEP MY WARRANTY!

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