#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; // NOLINT

const int64_t MOD = 998244353;

int64_t f(int64_t x, int64_t y) {
    if (y == 0)
        return 1;
    auto z = f(x, y / 2);
    z = z * z % MOD;
    if (y % 2)
        z = z * x % MOD;
    return z;
}

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