#include <bits/stdc++.h>
using namespace std;
#if __has_include(<atcoder/all>)
    #include <atcoder/all>
using namespace atcoder;
#endif
template<class T, class... Ts> void print(const T& a, const Ts&... b){cout << a;(cout << ... << (cout << ' ', b));cout << '\n';}
template<class... T> void input(T&... a){(cin >> ... >> a);}
void print(){cout << '\n';}
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> T;
typedef modint998244353 mint;
#define rep(i, n) for(ll i = 0; i < n; i++)

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    
    ll n,m; input(n,m);
    if(n < m)return print(0),0;
    vector<mint> r(100,0);
    r[0] = 1; r[1] = 2;
    for(int i=2;i<=100;i++)r[i] = r[i-1]*r[i-1];
    ll cnt = 1;
    mint t1 = 1,t2 = 1;
    while(n){
        if(n & 1)t1 *= r[cnt];
        n >>= 1;
        cnt++;
    }
    m--;
    cnt = 1;
    while(m){
        if(m & 1)t2 *= r[cnt];
        m >>= 1;
        cnt++;
    }
    print((t1-t2).val());
    
    return 0;
}