#pragma GCC optimize("Ofast") #include <bits/stdc++.h> using namespace std; typedef long long int ll; constexpr ll mod = 998244353; ll mod_pow(ll a,ll b){ a%=mod; if(b==0)return 1; if(b==1)return a; ll res=mod_pow(a,b/2)%mod; res*=res; res%=mod; if(b%2)res*=a; return res%mod; } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); ll n,m; cin >> n >> m; if(n<m){ cout << 0 << endl; return 0; } ll res = mod_pow(2, n); ll sub = 1; for(int i=0;i<m;i++){ // res -= p.comb(n,i) res -= sub; sub *= (n-i)%mod; sub %= mod; sub *= mod_pow(i+1, mod-2); sub %= mod; } res %= mod; cout << (res+mod)%mod << endl; }