#include <bits/stdc++.h>

using namespace std;

using ll = long long;
template <class T = int> using V = vector<T>;
template <class T = int> using VV = vector<V<T>>;
template <class T = int> using VVV = vector<VV<T>>;
template<class T>bool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; }
template<typename T> void view(T e){std::cout << e << std::endl;}
template<typename T> void view(const std::vector<T>& v){for(const auto& e : v){ std::cout << e << " ";} std::cout << std::endl;}
template<typename T> void view(const std::vector<std::vector<T> >& vv){ for(const auto& v : vv){ view(v); } }

#define rep(i, n) for(int i = 0; i < (int) n; i++)

const int mod = 998244353;
// const int mod = 1000000007;
struct modint {
    ll a = 0;
    modint(ll x = 0) {while(x < 0)x += mod;a = x%mod;}
    modint(const modint &r) {a = r.a;}
  modint operator -(){return modint(-a);}
  modint operator +(const modint &r) {return modint(*this)+=r;}
  modint operator -(const modint &r) {return modint(*this)-=r;}
  modint operator *(const modint &r) {return modint(*this)*=r;}
    modint &operator +=(const modint &r){
      a += r.a;
      if(a >= mod) a -= mod;
      return *this;
  }
  modint &operator -=(const modint &r) {
      a -= r.a;
      if(a < 0) a += mod;
      return *this;
  }
  modint &operator *=(const modint &r) {
      a = a * r.a % mod;
      return *this;
  }
  modint pow(ll r) const {
      if (!r) return 1;
      modint x = pow(r >> 1);
      x *= x;
      if (r & 1) x *= *this;
      return x;
  }
  modint inverse() const {
      return pow(mod-2);
  }
  modint& operator/=(const modint r) {
      return (*this) *= r.inverse();
  }
  modint operator/(const modint r) const {
      modint res(*this);
      return res /= r;
  }
};
 
istream &operator>>(istream &is, modint &x) {
    ll t;
    is >> t;
    x = t;
    return is;
}
ostream &operator<<(ostream &os, const modint& x) {
    return os << x.a;
}
const int MAX = 100044;
modint fac[MAX], inv[MAX], finv[MAX];
void cominit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i = 2; i < MAX; i++) {
        fac[i] = fac[i-1] * modint(i);
        inv[i] = - inv[mod%i] * modint(mod/i);
        finv[i] = finv[i-1] * inv[i];
    }
}
modint Com(ll n, ll k) {
    if(n < k) return 0;
    if(n < 0 || k < 0) return 0;
    return fac[n] * finv[k] * finv[n - k];
}
modint Per(ll n, ll k) {
    if(n < k) return 0;
    if(n < 0 || k < 0) return 0;
    return fac[n] * finv[n - k];
}
 
using mint = modint;

int main() {
    ll n, m;
    cin >> n >> m;
    cominit();
    mint ans = mint(2).pow(n);
    V<mint> calc(m + 1, 1);
    for (int i = 1; i <= m; i++) {
        calc[i] = calc[i - 1] * (n - i + 1);
    }
    for (int i = 0; i < m; i++) {
        ans -= calc[i] * finv[i];
    }
    cout << ans << endl;
}