// 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):
    return fac(n)/(fac(k)*fac(n-k))