R={\frac{(Int(\frac{b}{2})+Int(\frac{c}{2}))! }{(Int(\frac{b}{2}))! (Int(\frac{c}{2}))!}}+\frac{\frac{n!}{b!c!}{}-{}{ \frac{(Int(\frac{b}{2})+Int(\frac{c}{2}))! }{(Int(\frac{b}{2}))! (Int(\frac{c}{2}))!}}\cdot{n}}{2n}