#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint998244353;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vmi = vector<mint>;
using vvmi = vector<vmi>;
using vvvmi = vector<vvmi>;
#define all(a) (a).begin(), (a).end()
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define rep(i, n) rep2(i, 0, n)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define drep(i, n) drep2(i, n, 0)


int main(){
    ll n, m; cin>> n >> m;
    if(n < m){
        cout << 0 << endl;
        return 0;
    }
    mint ans = mint(2).pow(n);
    mint tmp = mint(0);
    mint ncr = mint(1);

    rep(i, m){
        tmp += ncr;
        ncr *= mint(n-i)/mint(i+1);
    }
    cout << (ans-tmp).val() << endl;

    return 0;
}