#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i < (int)(n+1); i++)
#define repn(i,a,b) for (int i = (int)(a) ; i < (int)(b+1); i++)
#define repv(i, n) for (int i = (int)(n-1); i >= 0; i--)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define sz(x) ((int)(x).size())
#define cauto const auto&
#define bit(n) (1LL<<(n))
#define uni(v) v.erase( unique(v.begin(), v.end()), v.end() );
using ll = long long;
using P = pair<int,int>;
using PP = pair<int, P>;
using Graph = vector<vector<int>>;
#ifdef LOCAL
    #include <debug.hpp>
    #define debug(...) debug::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
    #define debug(...) (static_cast<void>(0))
#endif

vector<ll> fac(510000,0),finv(510000,0),inv(510000,0);

void init() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < 510000; i++){
        fac[i] = (fac[i - 1] * i )% 998244353;
        inv[i] = (-inv[998244353%i] * (998244353/ i)) % 998244353 ;
        finv[i] =( finv[i - 1] * inv[i] ) % 998244353;
    }
}

ll combination(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return (fac[n] * (finv[k] * finv[n - k] % 998244353)) % 998244353;
}

ll pow_mod(ll a, ll b, ll mod = 998244353){
    ll res = 1;
    while(b > 0){
        if(b & 1) res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return res;
}

int main(){
    int n,k;
    cin >> n >> k;
    ll ans = 0;
    init();
    rep1(i,n-1){
        ans += combination(n-1,i) * pow_mod(i,k) % 998244353;
        ans %= 998244353;
    }
    if(ans < 0){
        ans += 998244353;
    }
    cout << ans << endl;
    return 0;
}