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

    def cmb(n, r, p):
        if (r < 0) or (n < r):
            return 0
        r = min(r, n - r)
        return fact[n] * factinv[r] * factinv[n-r] % p

    if n < 10**6:
        p = 998244353
        N = 10 ** 3  # N は必要分だけ用意する
        fact = [1, 1]  # fact[n] = (n! mod p)
        factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
        inv = [0, 1]  # factinv 計算用

        for i in range(2, N + 1):
            fact.append((fact[-1] * i) % p)
            inv.append((-inv[p % i] * (p // i)) % p)
            factinv.append((factinv[-1] * inv[-1]) % p)

        print(cmb(n, k, MOD))

    else:
        print(nCr(n, k, MOD))

if __name__ == '__main__':
    solve()