#include <iostream>
#include <algorithm>

using namespace std;

const long long MOD = 998244353;

long long power(long long a, long long b, long long m) {
    long long res = 1;
    a %= m;
    while (b > 0) {
        if (b & 1) {
            res = (res * a) % m;
        }
        a = (a * a) % m;
        b >>= 1; 
    }
    return res;
}

long long modInverse(long long a, long long m) {
    return power(a, m - 2, m);
}

long long solve_nck(long long N, long long K) {
    if (K == 0 || K == N) {
        return 1;
    }
    if (K < 0 || K > N) {
        return 0;
    }
    
    if (N%MOD == 0) return 0;

    if (K > N - K) {
        K = N - K;
    }

    long long numerator = 1;   
    long long denominator = 1; 

    for (long long i = 1; i <= K; ++i) {
        numerator = (numerator * (N - i + 1)) % MOD;

        denominator = (denominator * i) % MOD;
    }

    long long inv_denominator = modInverse(denominator, MOD);
    
    return (numerator * inv_denominator) % MOD;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    long long N, K;
    cin >> N >> K;

    long long result = solve_nck(N, K);
    cout << result << endl;

    return 0;
}