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

// #include<ext/pb_ds/assoc_container.hpp>
// #include<ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
// typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds; // find_by_order, order_of_key


#define IOS ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl "\n"
#define int long long


// int dx[4]={-1,0,1,0};
// int dy[4]={0,1,0,-1};

// int dx[8]={0,-1,-1,-1,0,1,1,1};
// int dy[8]={1,1,0,-1,-1,-1,0,1};


const int mod = 998244353;
using ii = pair<int,int>;

//write on copy

// 779869259


int add(int a, int b)
{
    return ((a%mod)+(b%mod))%mod;
}


void solver(){
    int n,k;
    cin>>n>>k;

    if(k>n)
    {
        cout<<1<<endl;return;
    }

    vector<int>dp(n+1,0);

    int ans = 2;
    dp[k]=1;

    for(int i=k+1;i<=n;i++)
    {
        dp[i]=add(dp[i-1],dp[i-k]);
        ans = add(ans, dp[i]);
    }

    cout<<ans<<endl;
}


signed main()
{
    IOS
    //int _t;cin>>_t;while(_t--)
    solver();
    return 0;
}

#undef int