// Binomial Coeffizient, n!/(k!*(n-k)!).
def fac(x):
    f = 1
    counter = 0
    for i in 1..100 do
        f = if counter == x then f else f * i fi
        counter = if counter == x then counter else counter + 1 fi
    endfor
    return f
def main(n, k):
    top = fac(n)
    bot1 = fac(k)
    sub = n - k
    bot2 = fac(sub)
    bot = bot1 * bot2
    return top / bot