#ifdef DEBUG
#define _GLIBCXX_DEBUG
#endif
//#pragma GCC optimize("O3")
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const ll mod = 998244353;
ll mult(ll a, ll b) {
    return (1LL * (a % mod) * (b % mod)) % mod;
}
ll sub(ll a, ll b) {
    ll s = (a - b) % mod;
    if (s < 0) s += mod;
    return s;
}
ll sum(ll a, ll b) {
    ll s = (a + b) % mod;
    if (s < 0) s += mod;
    return s;
}
ll pw(ll a, ll b) {
    if (b == 0) return 1;
    if (b & 1) return mult(a, pw(a, b - 1));
    ll res = pw(a, b / 2);
    return mult(res, res);
}
void solve() {
    ll n, m;
    cin >> n >> m;
    ll alpha = sub(mult(n, n), mult(n, 2));
    ll div_n = pw(n, mod - 2);
    alpha = mult(alpha, mult(div_n, div_n));
    ll beta = mult(2, mult(div_n, div_n));
    assert(alpha != 1);
    ll D = mult(beta, pw(sub(1, alpha), mod - 2));
    ll ini = sub(1, D);
    ini = mult(ini, pw(alpha, m));
    ini = sum(ini, D);
    ini = sub(1, ini);
    cout << mult(n, ini) << '\n';
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
#ifdef DEBUG
    freopen("input.txt", "r", stdin);
#endif
    int tst;
    cin >> tst;
    while (tst--) {
        solve();
    }
    return 0;
}