procedure main()
    write("P(4,2) = ",P(4,2))
    write("P(8,2) = ",P(8,2))
    write("P(10,8) = ",P(10,8))
    write("C(10,8) = ",C(10,8))
    write("C(20,8) = ",C(20,8))
    write("C(60,58) = ",C(60,58))
    write("P(1000,10) = ",P(1000,10))
    write("P(1000,20) = ",P(1000,20))
    write("P(15000,2) = ",P(15000,2))
    write("C(1000,10) = ",C(1000,10))
    write("C(1000,999) = ",C(1000,999))
    write("C(1000,1000) = ",C(1000,1000))
    write("C(15000,14998) = ",C(15000,14998))
end

procedure C(n,k)
    every (d:=1) *:= 2 to k
    return P(n,k)/d
end

procedure P(n,k)
    every (p:=1) *:= (n-k+1) to n
    return p
end