use formula (n+a)!/(a!n!)*(n+b)!/(b!n!)
all the variables should have type 'unsigned __int64'

Dear jedumastex!
It's really great that you have written the formula on a blyudechko with a light-blue koyomochka, but could you please be so kind as to PROVE(or at lest explain) why on earth does the formula work? Thanks in advance. My email is LordN3mrod@gmail.com