#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define srep(i,l,r) for(ll i=l;i<=r;i++)
#define irep(i,r,l) for(ll i=r;i>=l;i--)
using ll = long long;
using ld = long double;
const ll mod=998244353;
#define vout(v) for(auto i :v) cout<<i<<" ";
#define INF 9223300000000000000ll
#define Winf 5e12
#define nl "\n"
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define vl vector<ll>
#define pb push_back
#define vc vector<char>


void no() { cout<<"No"<<nl;}
void yes() { cout<<"Yes"<<nl;}
void yn(bool a) {
    cout<<(a ? "Yes":"No")<<nl;
}



template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
ll c(ll n,ll k) {
    vector<vector<ll>> dp(2*n+1,vl(k+2));
    dp[0][0]=1;
    rep(i,2*n) {
        srep(d,0,k) {
            if(d<k) {
                dp[i+1][d+1]=(dp[i+1][d+1]+dp[i][d])%mod;
            }
            if(d>0) {
                dp[i+1][d-1]=(dp[i+1][d-1]+dp[i][d])%mod;
            }
        }
    }
    return dp[2*n][0];
}


int main() {
    ll n,k; cin>>n>>k;
    ll a=c(n,k),b=c(n,k-1);
    cout<<(a-b+mod)%mod<<nl;
}