Sereja and Number Division 2

I have a problem with the SEAND2 in the January 2015 Long Challenge.
I’m not sure get the description correctly or not.
According to problem description the answer of second test case of the example shoud be 754321, because of f(754321) = 1; but in the sample output the answer shows as 754312. So f(754312) = 2, that’s less optimal than 1.
What’s wrong with my understanding?

It was already discussed -

@betlista I check, but I didn’t get it! could you please explain it more?
Thanks for your reply.