How many men can a woman sleep with before she is branded a "whore"?

I see a lot of"we don't expect virgin unicorns, we just don't want a whore". Well, what is a whore in this context? A woman who has had sex with 4 men in LTRs and 3 casual sex partners in her mid-20s? A woman the same age who has had ANY casual sex partners instead of LTRs? Is a mid-20s woman who has had more sex partners than LTRS a whore even the total is still under, say, 7? How about a woman who has had more sex partners than you, but the number is still under 10?

Does "riding the CC" refer to any woman simply not seeking a serious relationship?

What's the actual equation when men here speak about women like this they'd never want?