from operator import mul
from functools import reduce
def cmb(n,r):
    r = min(n-r,r)
    if r==0:return 1
    over=reduce(mul,range(n,n-r,-1))
    under=reduce(mul,range(1,r+1))
    return over//under
N,K=map(int,input().split())
a=cmb(N,K)
print(a%998244353)