#include <bits/stdc++.h>
#include <atcoder/modint.hpp>
using namespace std;

using i32 = int;
using i64 = long long;
using i128 = __int128_t;
using f64 = double;
using p2 = pair<i64, i64>;
using p3 = tuple<i64, i64, i64>;
using mint = atcoder::modint;
constexpr i64 inf = 1e18;

void _main();
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(18);
  _main();
}

void _main() {
  i64 tt;
  cin >> tt;
  for (;tt--;) {
    i64 n, m;
    cin >> n >> m;
    mint ans = 1;
    ans *= mint(m).pow(n - 2);
    ans *= mint(m) * mint(m - 1) / 2 * mint(m);
    ans *= mint(n) * mint(n - 1) / 2;
    cout << ans.val() << "\n";
  }
}