#include <iostream>
#include <vector>

const int MOD = 998244353;

using namespace std;

// ???? ????? ?????? ????????
vector<long long> factorial(int n) {
    vector<long long> fact(n + 1, 1);
    for (int i = 2; i <= n; ++i) {
        fact[i] = (fact[i - 1] * i) % MOD;
    }
    return fact;
}

// ???? ????? ??????? ???????? ???? ?????
long long modInverse(long long a, long long p) {
    long long result = 1;
    long long exponent = p - 2; // p ?? ??? ????
    while (exponent) {
        if (exponent % 2 == 1) {
            result = (result * a) % p;
        }
        a = (a * a) % p;
        exponent /= 2;
    }
    return result;
}

// ???? ????? ??? ????? ?????? ????
long long countTrees(int N, int P) {
    if (P > N) return 0; // ??? ??? ??? ?????????? ??????? ???? ?? ??????
    
    long long totalWays = 0;
    auto fact = factorial(N);

    // ???? ??? ?????
    for (int k = P; k <= N; ++k) {
        long long ways = (fact[N - k] * modInverse(fact[k], MOD)) % MOD;
        ways = (ways * modInverse(fact[N - k - P], MOD)) % MOD;
        totalWays = (totalWays + ways) % MOD;
    }

    return totalWays;
}

int main() {
    int N, P;
    cin >> N >> P;

    cout << countTrees(N, P) << endl;

    return 0;
}