That's probably because whoever submitted the hint can't pronounce "F" and the Korean language literally does not have a "F". For example "fried" would be pronounced "hooride". Much similar to how Japanese and Korean language don't have a "R" and is substituted with "L". nleconte is correct. "Pan" is obviously wrong here while "Fan" is correct.
Because if a band does not have one fan, neither do they have many. In english you could say "he doesn't have a brother" or "he has no brothers" and it means the same