#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using ll = long long;
using mint = atcoder::modint998244353;
const ll INF = LLONG_MAX / 4;
#define rep(i,a,b) for(ll i = a; i < b; i++)
template<class T, class U> bool chmax(T& a, U b){ if(a >= b) return 0; a = b; return 1; }


int main(){
    ll N, M;
    cin >> N >> M;
    if(N < M) return puts("0") & 0;
    mint ans = mint{2}.pow(N), c = 1;
    for(ll i = 0; i < M; i++){
        ans -= c;
        c *= N - i;
        c /= i + 1;
    }
    cout << ans.val() << endl;
}