#include <bits/stdc++.h>
#define int long long
#define endl "\n"
using namespace std;
int MOD = 998244353;

int binpow(int a, int p)
{
  if (p==0) return 1;
  if (p%2) return binpow(a,p-1)*a%MOD;
  int t=binpow(a,p/2);
  return t*t%MOD;
}

void solve()
{
  int n,m;
  cin>>n>>m;
  
  cout << (
    binpow((binpow(2,n)-1+MOD)%MOD,m)-
      (binpow(binpow(2,m),n)-
        binpow((binpow(2,m)-1+MOD)%MOD,n)+MOD)%MOD+MOD
    )%MOD << endl;
}

signed main()
{
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  
  int t;cin>>t;while(t--)
  solve();
}