Roulette

 

 

 

 

#include<iostream>

#include<algorithm>

#include<cmath>

#include<cstdio>

#include<string>

#include<cstring>

#include<queue>

#include<set>

#include<map>

#include<vector>

#include<stack>

#define scanf scanf_s

using namespace std;

#define int long long

const int mod = 998244353;

 

int fpow(int x, int b)

{

    if (x == 0) return 0;

    if (b == 0) return 1;

    int res = 1;

    while (b > 0)

    {

        if (b & 1)  res = 1LL * res * x % mod;

        x = 1LL * x * x % mod;

        b >>= 1;

    }

    return res;

}

int calc(int x)

{

    int res = 0;

    for (int i = 1;; i *= 2)

    {

        if (x < i) break;

        res++, x -= i;

    }

    return res;

}

 

signed main()

{

    int n, m;

    cin >> n >> m;

    int ans = 1;

    int l = n, r = n + m - 1;

    while (l <= r)

    {

        int L = l, R = r, res = L;

        while (L <= R)

        {

            int mid = (L + R) >> 1;

            if (calc(mid) == calc(l)) res = mid, L = mid + 1;

            else R = mid - 1;

        }

        int prob = (1 - fpow(499122177, calc(l)) + mod) % mod;

        ans = ans * fpow(prob, res - l + 1) % mod;

        l = res + 1;

    }

    cout << ans << "\n";

    return 0;

}