#include <iostream>
#include <algorithm>
using namespace std;

const long long MOD = 998244353;

long long modPow(long long base, long long exp, long long mod) {
    long long result = 1;
    base %= mod;
    while (exp > 0) {
        if (exp & 1) 
            result = (result * base) % mod;
        base = (base * base) % mod;
        exp >>= 1;
    }
    return result;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    long long N, K;
    cin >> N >> K;
    
    if (K == 0) {
        cout << 1 << '\n';
        return 0;
    }
    
    if (K > N - K) {
        K = N - K;
    }
    
    long long n0 = N % MOD;
    long long n1 = N / MOD;
    
    if (K > n0) {
        cout << 0 << '\n';
        return 0;
    }
    
    long long k = min(K, n0 - K);
    if (k == 0) {
        cout << 1 << '\n';
        return 0;
    }
  
    long long numerator = 1;
    long long denominator = 1;
    for (long long i = 0; i < k; i++) {
        numerator = numerator * ((n0 - i) % MOD) % MOD;
        denominator = denominator * (i + 1) % MOD;
    }
    
    long long inv_den = modPow(denominator, MOD - 2, MOD);
    cout << numerator * inv_den % MOD << '\n';
    
    return 0;
}