#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;
}

long long smallC(long long n, long long k) {
    if (k < 0 || k > n) return 0;
    if (k == 0 || k == n) return 1;
    k = min(k, n - k);
    
    long long num = 1, den = 1;
    for (long long i = 0; i < k; ++i) {
        num = num * ((n - i) % MOD) % MOD;
        den = den * (i + 1) % MOD;
    }
    return num * modPow(den, MOD - 2, MOD) % MOD;
}

long long lucas(long long n, long long k) {
    if (k < 0 || k > n) return 0;
    long long res = 1;
    while (n || k) {
        long long ni = n % MOD;
        long long ki = k % MOD;
        if (ki > ni) return 0;
        res = res * smallC(ni, ki) % MOD;
        n /= MOD;
        k /= MOD;
    }
    return res;
}

int main() {
    long long N, K;
    cin >> N >> K;
    
    if (K > N-K) K = N-K; 
    
    cout << lucas(N, K) << '\n';
    
    return 0;
}