#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 998244353;
constexpr double PI = 3.14159265358979323846;

long long modpow(long long x, long long n) {
    long long ret = 1;
    while (n > 0) {
        if (n & 1) ret = (ret * x) % MOD;  
        x = (x * x) % MOD;
        n >>= 1;  
    }
    return ret;
}

int main(){
    ll n,l;
    scanf("%lld%lld",&n,&l);
    ll p = (n%l==0)?(n/l-1):(n/l);
    cout << modpow(2,p+1)-1 << endl;
    return 0;
}