#include <bits/stdc++.h>

#include <atcoder/all>

#define rep(i, n) for (int i = 0, i##_len = (n); i < i##_len; ++i)
#define all(v) begin(v), end(v)
using namespace std;
using namespace atcoder;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    using mint = modint998244353;
    using P = pair<mint, mint>;
    int Q;
    cin >> Q;
    while (Q--) {
        int n;
        cin >> n;
        vector<P> z(n);
        rep(i, n) {
            int l, r;
            cin >> l >> r;
            z[i] = {l, r};
        }
        mint A = 0, B = 0, C = 0, D = 0, E = 0, F = 0, G = 0;
        rep(i, n) {
            auto [x, y] = z[i];
            mint xxyyI = mint(1) / (x * x + y * y);
            A += (2 * x * x) * xxyyI;
            B += (8 * x * y) * xxyyI;
            C += (2 * y * y) * xxyyI;
            D += x * x;
            E += y * y;
            F += x * x * xxyyI * xxyyI;
            G += y * y * xxyyI * xxyyI;
        }

        mint ans = 0;
        rep(i, n) {
            auto [a, b] = z[i];
            mint aabbI = mint(1) / (a * a + b * b);
            ans += -A * (a * a) * aabbI;
            ans += A * (b * b) * aabbI;
            ans += -B * a * b * aabbI;
            ans += C * (a * a) * aabbI;
            ans += -C * (b * b) * aabbI;
            ans += D * (a * a) * aabbI * aabbI;
            ans += D * (b * b) * aabbI * aabbI;
            ans += E * (a * a) * aabbI * aabbI;
            ans += E * (b * b) * aabbI * aabbI;
            ans += F * (a * a);
            ans += F * (b * b);
            ans += G * (a * a);
            ans += G * (b * b);
        }
        ans /= 2;
        cout << ans.val() << endl;
    }
    return 0;
}