#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int tt;
  cin >> tt;
  while (tt--) {
    int n;
    cin >> n;
    mint ans;
    mint c1, cx4, cy4, cxy, cxy2, cx2, cy2;
    rep(i, n) {
      int xi, yi;
      cin >> xi >> yi;
      mint x = xi, y = yi;
      mint x2 = x * x, y2 = y * y;
      mint x4 = x2 * x2, y4 = y2 * y2;
      mint inv = (x2 + y2).inv();
      ans += (c1 + cx4 * x4 + cy4 * y4 + cy2 * y2 + cxy2 * x2 * y2 + cxy * x * y + cx2 * x2) * inv;
      c1 += (x4 + 2 * x2 * y2 + y4) * inv;
      cx2 += (-2 * x2 + 2 * y2) * inv;
      cxy += (-8 * x * y) * inv;
      cxy2 += (2) * inv;
      cy2 += (2 * x2 - 2 * y2) * inv;
      cx4 += (1) * inv;
      cy4 += (1) * inv;
    }
    cout << ans.val() << '\n';
  }
}