#include <bits/stdc++.h>
using namespace std;

#include <atcoder/all>
using namespace atcoder;
using mint=modint998244353;

int main(void) {
    int n,k;
    cin >> n >> k;
    vector<mint> inv(2*n+5,1);
    vector<mint> fact(2*n+5,1);
    vector<mint> finv(2*n+5,1);
    for(int i=2;i<=2*n+4;++i){
        inv[i]=mint(i).inv();
        fact[i]=fact[i-1]*i;
        finv[i]=finv[i-1]*inv[i];
    }
    mint ans=fact[2*n+4]*finv[k]*finv[2*n+4-k];
    if(n%2==0){
        if(k%2==0){
            ans+=fact[n+2]*finv[k/2]*finv[n+2-k/2]*3;
        }
    } else {
        if(k%2==0){
            ans+=fact[n+2]*finv[k/2]*finv[n+2-k/2]*2;
            ans+=fact[n+1]*finv[k/2]*finv[n+1-k/2];
            ans+=fact[n+1]*finv[(k-2)/2]*finv[n+1-(k-2)/2];
        } else {
            ans+=fact[n+1]*finv[(k-1)/2]*finv[n+1-(k-1)/2]*2;
        }
    }
    ans/=4;
    cout << ans.val() << endl;
    return 0;
}