In 48 hours you have 281,474,976,710,656 people

No country would be able to help but nuke the entire country this starts in just to stop it, but that would already be too late

Even if dude didn’t want to take over the world, he would do it unintentionally by collapsing every system just by sheer numbers. Within a week all of these copies are mass cannibalizing out of hunger and dumping remains into the ocean just to make room. Within a month, the sea levels literally begin to rise from the amount of bodies being dumped into the ocean and polar caps melting from mass body burning in any area not near a coast and every single car in every single car lot being stolen

Every single copy with a blade or a gun would have to begin killing each of their copies as soon as it comes in every hour for the rest of their life, and then eating them because all conventional plants and animal have either been eaten or claimed by factions that most likely begin to arise, then it would all turn into some Rick and Morty shit until everyone collectively decides to kill themselves either through nukes, the apocalypse, or collective suicide

Unless of course dude can control whether or not he can copy, in which case he still definitely takes over the world since every copy knows as well as he does to hide and keep copying until the time is right