#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <tuple>
#include <cstdint>
#include <cstdio>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <deque>
#include <unordered_map>
#include <unordered_set>
#include <bitset>
#include <cctype>
#include <climits>
#include <functional>
#include <cassert>
#include <numeric>
#define rep(i, n) for(int i = 0; i < (n); i++)
#define per(i, n) for(int i = (n) - 1; i >= 0; i--)
using ll = long long;
#define vi vector<int>
#define vvi vector<vi>
#define vl vector<ll>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
constexpr int mod = 998244353;
using namespace std;
template<class T, class U>
bool chmax(T &a, const U &b){ return a < b ? (a = b, 1) : 0; }
template<class T, class U>
bool chmin(T &a, const U &b){ return a > b ? (a = b, 1) : 0; }
template <int mod>
struct Mint {
  ll x;
  constexpr Mint(ll x = 0) : x((x + mod) % mod){}
  static constexpr int get_mod(){ return mod; }
  constexpr Mint operator-() const{ return Mint(-x); }
  constexpr Mint operator+=(const Mint &a){
    if((x += a.x) >= mod) x -= mod;
    return *this;
  }
  constexpr Mint &operator++(){
    if(++x == mod) x = 0;
    return *this;
  }
  constexpr Mint operator++(int){
    Mint temp = *this;
    if(++x == mod) x = 0;
    return temp;
  }
  constexpr Mint &operator-=(const Mint &a){
    if((x -= a.x) < 0) x += mod;
    return *this;
  }
  constexpr Mint &operator--(){
    if(--x < 0) x += mod;
    return *this;
  }
  constexpr Mint operator--(int){
    Mint temp = *this;
    if(--x < 0) x += mod;
    return temp;
  }
  constexpr Mint &operator*=(const Mint &a){
    (x *= a.x) %= mod;
    return *this;
  }
  constexpr Mint operator+(const Mint &a) const{ return Mint(*this) += a; }
  constexpr Mint operator-(const Mint &a) const{ return Mint(*this) -= a; }
  constexpr Mint operator*(const Mint &a) const{ return Mint(*this) *= a; }
  constexpr Mint pow(ll t) const{
    if(!t) return 1;
    Mint res = 1, v = *this;
    while(t){
      if(t & 1) res *= v;
      v *= v;
      t >>= 1;
    }
    return res;
  }
  constexpr Mint inv() const{ return pow(mod - 2); }
  constexpr Mint &operator/=(const Mint &a){ return (*this) *= a.inv(); }
  constexpr Mint operator/(const Mint &a) const{ return Mint(*this) /= a; }
  constexpr bool operator==(const Mint &a) const{ return x == a.x; }
  constexpr bool operator!=(const Mint &a) const{ return x != a.x; }
  constexpr bool operator<(const Mint &a) const{ return x < a.x; }
  constexpr bool operator>(const Mint &a) const{ return x > a.x; }
  friend istream &operator>>(istream &is, Mint &a){ return is >> a.x; }
  friend ostream &operator<<(ostream &os, const Mint &a){ return os << a.x; }
};
using mint = Mint<mod>;
int main(){
  ll n,m;
  cin >> n >> m;
  mint ans = mint(2).pow(n);
  mint val = 1;
  rep(i, m){
    ans -= val;
    val *= n - i;
    val /= i+1;
  }
  cout << ans << "\n";
}