#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

const int64_t MOD = 998244353;

int64_t f(int64_t x, int64_t n) {
    if (n == 0)
        return 1;
    int64_t ans = f(x, n / 2);
    ans = ans * ans % MOD;
    if (n % 2)
        ans = ans * x % MOD;
    return ans;
}

int main() {
    int64_t n, l;
    cin >> n >> l;
    n = max(n - l, int64_t(0)) + 1;
    int64_t ans = f(2, n);
    ans = (ans - 1 + MOD) % MOD;
    cout << ans << endl;
    return 0;
}