#include <bits/stdc++.h>
using namespace std;
#define int long long
int pow(int x, int n, int MOD) {
  int ret = 1;
  while (n > 0) {
    if (n & 1) ret = ret * x % MOD;
    x = x * x % MOD;
    n >>= 1;
  }
  return (ret+998244352)%MOD;
}
signed main(){
    int N,L;
    cin>>N>>L;
    int MOD = 998244353;
    cout<<pow(2,N-L+1,MOD)<<endl;
}