20240711

import syslimit_number = 1000000001sys.setrecursionlimit(limit_number)def s(y):    if y==1:        return y    return s(y-1)*ydef f(a,b):    global k    print(s(a)//(s(k)*s(b))%1999)y,u=map(int,input().split())k=y-uf(y,u)