#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;
}