#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
const int mod = 998244353;
//using mint = modint1000000007;
//const int mod = 1000000007;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int t; cin >> t;
	while (t--) {
		int n; cin >> n;
		mint ans = 0;
		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() << endl;
	}
	return 0;
}