//
// Created by 35395 on 2024/10/23.
//
#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e7 + 100, mod = 998244353;
int f[N],f_inv[N],inv[N];

void init(){
    inv[1] = f[0] = f_inv[0] = 1;
    for(int i=2;i<N;i++) inv[i] = 1ll*(mod - mod / i) * inv[mod % i] % mod;
    for(int i=1;i<N;i++) f[i] = 1ll*f[i-1] * i % mod;
    for(int i=1;i<N;i++) f_inv[i] = 1ll*f_inv[i-1] * inv[i] % mod;
}

int C(int a,int b){
    if(a < 0 || b < 0 || a < b) return 0;
    return 1ll*f[a] * f_inv[b] % mod * f_inv[a-b] % mod;
}

int n,m,c;

pair<int,int> get(int x,int y,int c){
    return {y-c,x+c};
}

void to(int &x,int &y,int c){
    auto [x_,y_] = get(x,y,c);
    x = x_, y = y_;
}

int get(int x,int y){
    int res = C(x+y,x);
    int nx = x, ny = y;
    while(nx >= 0 && ny >= 0){
        to(nx,ny,c); res = (res - C(nx+ny,nx) + mod) % mod;
        to(nx,ny,1); res = (res + C(nx+ny,nx)) % mod;
    }
    nx = x, ny = y;
    while(nx >= 0 && ny >= 0){
        to(nx,ny,1); res = (res - C(nx+ny,nx) + mod) % mod;
        to(nx,ny,c); res = (res + C(nx+ny,nx)) % mod;
    }
    return res;
}

signed main(){
    init();
    cin >> n >> m;
    int down = (n + 1) / 2;
    int ans = 0;
    c = -(m+1)/2 - 1;
    int cnt = 0;
    for(int i=down;i<=n && i <= n-i+(m+1)/2;i++){
        int j = n - i;
        ans = (ans + get(i,j)) % mod;
    }
    cout << ans << '\n';
}