def solve():
    n, k = map(int, input().split())

    MOD = 998244353

    def nCr(n, r, mod):
        if r < 0 or r > n:
            return 0

        r = min(r, n - r)

        if r == 0:
            return 1

        numerator = 1
        denominator = 1

        for i in range(r):
            numerator = (numerator * (n - i)) % mod
            denominator = (denominator * (i + 1)) % mod

        return (numerator * pow(denominator, mod - 2, mod)) % mod

    print(nCr(n, k, MOD))

if __name__ == '__main__':
    solve()