#include <bits/stdc++.h>

#define int long long

using namespace std;

const int N = 1e6 + 10;
const int mod = 998244353;

int fac[N], invfac[N];
int qmi(int a, int b = mod - 2) {
    int res = 1;
    while (b) {
        if (b & 1) res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }

    return res;
}

void init() {
    fac[0] = 1;
    for (int i = 1; i < N; i++) fac[i] = fac[i - 1] * i % mod;
    invfac[N - 1] = qmi(fac[N - 1]);
    for (int i = N - 2; i >= 0; i--) invfac[i] = invfac[i + 1] * (i + 1) % mod;
}

int C(int a, int b) {
    return fac[a] * invfac[b] % mod * invfac[a - b] % mod;
}

signed main() {
    init();
}