#include<bits/stdc++.h>
using namespace std;
using ll =long long;
using vll =vector<ll>;
#define all(A) A.begin(),A.end()
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)

vector<ll> power(70);
ll mod = 998244353;
void D(ll A) {
	rep(i, 70) {
		power[i] = 0;
	}
	power[0] = A;
	rep(i, 69) {
		power[i + 1] = power[i] * power[i];
		power[i + 1] %= mod;
	}
}
ll modpow(ll k) {
	ll P = k;
	ll res = 1;
	rep(i, 70) {
		if (P % 2 != 0) {
			res *= power[i];
			res %= mod;
		}
		P /= 2;
	}
	return res;
}//A^kを高速に求める。前処理D(A)、計算ともにO(log INF)

int main(){
    D(2);
    ll T;
    cin>>T;
    rep(t,T){
        ll N,K;
        cin>>N>>K;
        ll Q=modpow(N*K);
        ll P=modpow((N-1)*K);
        ll AN=N*(Q-P);
        AN%=mod;
        AN+=mod;
        AN%=mod;
        cout<<AN<<endl;
    }
}