#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define X first
#define Y second
#define SZ(a) ((int)a.size())
#define ALL(v) v.begin(), v.end()
#define pb push_back

const int MOD = 998244353;
const int N = 1 << 19;

void add(ll &x, ll val) {
    x = (x + val) % MOD;
}

ll pw(ll a, ll n) {
    ll rt = 1;
    for (; n; n >>= 1, a = a * a % MOD)
        if (n & 1)
            rt = rt * a % MOD;
    return rt;
}

//(2^16)+1, 65537, 3
//7*17*(2^23)+1, 998244353, 3
//1255*(2^20)+1, 1315962881, 3
//51*(2^25)+1, 1711276033, 29
template<int MAXN, ll P, ll RT> //MAXN must be 2^k
struct NTT {
  ll w[MAXN];
  ll mpow(ll a, ll n) {
    return pw(a, n);
  }
  ll minv(ll a) { return mpow(a, P - 2); }
  NTT() {
    ll dw = mpow(RT, (P - 1) / MAXN);
    w[0] = 1;
    for (int i = 1; i < MAXN; ++i) w[i] = w[i - 1] * dw % P;
  }
  void bitrev(ll *a, int n) {
    int i = 0;
    for (int j = 1; j < n - 1; ++j) {
      for (int k = n >> 1; (i ^= k) < k; k >>= 1);
      if (j < i) swap(a[i], a[j]);
    }
  }
  void operator()(ll *a, int n, bool inv = false) { //0 <= a[i] < P
    bitrev(a, n);
    for (int L = 2; L <= n; L <<= 1) {
      int dx = MAXN / L, dl = L >> 1;
      for (int i = 0; i < n; i += L) {
        for (int j = i, x = 0; j < i + dl; ++j, x += dx) {
          ll tmp = a[j + dl] * w[x] % P;
          if ((a[j + dl] = a[j] - tmp) < 0) a[j + dl] += P;
          if ((a[j] += tmp) >= P) a[j] -= P;
        }
      }
    }
    if (inv) {
      reverse(a + 1, a + n);
      ll invn = minv(n);
      for (int i = 0; i < n; ++i) a[i] = a[i] * invn % P;
    }
  }
};

NTT<N, MOD, 3> ntt;
int n;
ll dp[N], fac[N], ifac[N], kk[N];
ll a[N], b[N];

void dq(int l, int r) {
    if (l == r) {
        dp[l] = MOD - dp[l];
        add(dp[l], pw(n + l + 1, l) * ifac[l] % MOD);
        return;
    }
    int mid = (l + r) >> 1;
    dq(l, mid);
    int L = 1;
    for (; L < (r - l + 1) * 2; L <<= 1);
    fill(a, a + L, 0), fill(b, b + L, 0);
    for (int i = l; i <= mid; ++i)
        a[i - l] = dp[i];
    for (int i = 1; i <= r - l; ++i)
        b[i] = kk[i] * ifac[i] % MOD;
    ntt(a, L), ntt(b, L);
    for (int i = 0; i < L; ++i)
        a[i] = a[i] * b[i] % MOD;
    ntt(a, L, true);
    for (int i = mid + 1; i <= r; ++i)
        add(dp[i], a[i - l]);
    dq(mid + 1, r);
}

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    int m;
    cin >> n >> m, n -= m;
    fac[0] = 1;
    for (int i = 1; i <= m; ++i) {
        fac[i] = fac[i - 1] * i % MOD;
        kk[i] = pw(i, i);
    }
    ifac[m] = pw(fac[m], MOD - 2);
    for (int i = m - 1; i >= 0; --i)
        ifac[i] = ifac[i + 1] * (i + 1) % MOD;
    
    dq(0, m);

    cout << dp[m] * fac[m] % MOD << "\n";
    
    /*dp[0] = 1;
    for (int i = 1; i <= m; ++i) {
        dp[i] = pw(n + i + 1, i) * ifac[i] % MOD;
        for (int j = 0; j < i; ++j)
            add(dp[i], MOD - pw(i - j, i - j) * dp[j] % MOD * ifac[i - j] % MOD);
    }*/
}