#include <bits/stdc++.h> #include <atcoder/all> using namespace std; using namespace atcoder; typedef long long ll; #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--) #define repk(i, k, n) for (int i = k; i < (int)(n); i++) #define all(v) v.begin(), v.end() #define mod1 1000000007 #define mod2 998244353 #define mod3 100000007 #define vi vector<int> #define vs vector<string> #define vc vector<char> #define vl vector<ll> #define vvi vector<vector<int>> #define vvc vector<vector<char>> #define vvl vector<vector<ll>> #define vvvi vector<vector<vector<int>>> #define vvvl vector<vector<vector<ll>>> #define pii pair<int,int> #define pil pair<int,ll> #define pli pair<ll, int> #define pll pair<ll, ll> #define vpii vector<pair<int,int>> #define vpll vector<pair<ll,ll>> #define vvpii vector<vector<pair<int,int>>> #define vvpll vector<vector<pair<ll,ll>>> template<typename T> void debug(T e){ cerr << e << endl; } template<typename T> void debug(vector<T> &v){ rep(i, v.size()){ cerr << v[i] << " "; } cerr << endl; } template<typename T> void debug(vector<vector<T>> &v){ rep(i, v.size()){ rep(j, v[i].size()){ cerr << v[i][j] << " "; } cerr << endl; } } template<typename T> void debug(vector<pair<T, T>> &v){ rep(i,v.size()){ cerr << v[i].first << " " << v[i].second << endl; } } template<typename T> void debug(set<T> &st){ for (auto itr = st.begin(); itr != st.end(); itr++){ cerr << *itr << " "; } cerr << endl; } template<typename T> void debug(multiset<T> &ms){ for (auto itr = ms.begin(); itr != ms.end(); itr++){ cerr << *itr << " "; } cerr << endl; } template<typename T> void debug(map<T, T> &mp){ for (auto itr = mp.begin(); itr != mp.end(); itr++){ cerr << itr->first << " " << itr->second << endl; } } void debug_out(){ cerr << endl; } template <typename Head, typename... Tail> void debug_out(Head H, Tail... T){ cerr << H << " "; debug_out(T...); } ll my_pow(ll x, ll n, ll mod){ // 繰り返し二乗法.x^nをmodで割った余り. ll ret; if (n == 0){ ret = 1; } else if (n % 2 == 1){ ret = (x * my_pow((x * x) % mod, n / 2, mod)) % mod; } else{ ret = my_pow((x * x) % mod, n / 2, mod); } return ret; } ll inv(ll x, ll mod){ return my_pow(x, mod - 2, mod); } int main(){ ll N,M; cin >> N >> M; if (N < M){ cout << 0 << endl; return 0; } ll ans = my_pow(2LL, N, mod2); ll rem = 1; for (ll i = 0; i < M; i++){ ans = (ans - rem + mod2) % mod2; rem = (rem * ((N - i) % mod2)) % mod2; rem = (rem * (inv(i + 1, mod2))) % mod2; } cout << ans << endl; }