//g++ 2.cpp -std=c++14 -O2 -I .
#include <bits/stdc++.h>
using namespace std;

#include <atcoder/all>
using namespace atcoder;

using ll = long long;
using ld = long double;

using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vld = vector<ld>;
using vvld = vector<vld>;
using vst = vector<string>;
using vvst = vector<vst>;

#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define pq_big(T) priority_queue<T,vector<T>,less<T>>
#define pq_small(T) priority_queue<T,vector<T>,greater<T>>
#define all(a) a.begin(),a.end()
#define rep(i,start,end) for(ll i=start;i<(ll)(end);i++)
#define per(i,start,end) for(ll i=start;i>=(ll)(end);i--)
#define uniq(a) sort(all(a));a.erase(unique(all(a)),a.end())

using mint = modint998244353;
constexpr ll mod = 998244353;

const int MAX=510000;
const long long MOD=998244353;

long long fac[MAX],finv[MAX],inv[MAX];

void COMinit(){
  fac[0]=fac[1]=1;
  finv[0]=finv[1]=1;
  inv[1]=1;
  for(int i=2;i<MAX;i++){
    fac[i]=fac[i-1]*i%MOD;
    inv[i]=MOD-inv[MOD%i]*(MOD/i)%MOD;
    finv[i]=finv[i-1]*inv[i]%MOD;
  }
}

long long COM(int n,int k){
  if(n<k) return 0;
  if(n<0||k<0) return 0;
  return fac[n]*(finv[k]*finv[n-k]%MOD)%MOD;
}

ll n,m;
mint ans=0;
int failed=0;
clock_t start;

mint f(vi &a){
  vi pw2(m+1);
  rep(i,0,n){
    pw2[a[i]]++;
  }
  rep(i,0,m+1){
    pw2[i]=pow_mod(2,pw2[i],mod);
  }

  mint res=0;
  mint now=pow_mod(2,n,mod);
  rep(i,1,m+2){
    now*=pw2[i-1]-1;
    now/=pw2[i-1];
    res+=now;
  }

  return res;
}

void dfs(int n,int m,vi &a){
  clock_t now=clock();
  if((double)(now-start)/CLOCKS_PER_SEC>=1.90){
    failed=1;
    return;
  }
  if(a.size()==n){
    ans+=f(a);
    return;
  }
  rep(i,0,m+1){
    a.emplace_back(i);
    dfs(n,m,a);
    a.pop_back();
  }
}

void solve1(){
  vi a={};

  dfs(n,m,a);

  assert(failed==0);

  cout<<ans.val()<<endl;
}

void solve2(){
  mint dp[min(n,m+1)+10][2*n]={};
  rep(i,0,min(n,m+1)){
    clock_t now=clock();
    if((double)(now-start)/CLOCKS_PER_SEC>=1.90){
      failed=1;
      break;
    }
    
    if(i==0){
      rep(k,0,n+1){
        // 0にk個割り当てる
        ll cm=COM(n,k);
        ll pw2=pow_mod(2,k,mod)-1;
        mint now=cm*pw2;
        dp[i][k]=now;
      }
      continue;
    }
    rep(j,0,n+1){
      now=clock();
      if((double)(now-start)/CLOCKS_PER_SEC>=1.90){
        failed=1;
        break;
      }
        
      rep(k,0,n+1){
        // 既にj個割り当てている + iにk個割り当てる
        if(j+k>n)continue;
        ll cm=COM(n-j,k);
        ll pw2=pow_mod(2,k,mod)-1;
        mint now=cm*pw2;
        dp[i][j+k]+=now*dp[i-1][j];
      }
    }
  }

  mint ans=0;
  rep(i,0,min(n,m+1)){
    rep(j,0,n+1){
      ans+=dp[i][j]*pow_mod(2*(m-i),n-j,mod);
    }
  }
  
  assert(failed==0);

  cout<<ans.val()<<endl;
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  start=clock();

  COMinit();

  cin>>n>>m;

  //solve1();
  solve2();
}