#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)
#define all(a) (a).begin(),(a).end()

#include <atcoder/modint>
using namespace atcoder;
using mint = modint998244353;

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    
    int T;
    cin >> T;
    
    rep(testcase, 0, T) {
        int N;
        cin >> N;
        vector<ll> X(N), Y(N);
        rep(i, 0, N) cin >> X[i] >> Y[i];
        
        mint v = 0, inv = 0;
        rep(i, 0, N) {
            mint abssq = X[i]*X[i] + Y[i]*Y[i];
            v += abssq;
            inv += 1 / abssq;
        }
        mint ans = v * inv;
        ans -= N;
        
        mint t1 = mint(X[0]*X[0] - Y[0]*Y[0]) / mint(X[0]*X[0] + Y[0]*Y[0]);
        mint t2 = mint(2 * X[0] * Y[0]) / mint(X[0]*X[0] + Y[0]*Y[0]);
        rep(i, 1, N) {
            mint abssq = X[i]*X[i] + Y[i]*Y[i];
            mint invabssq = 1 / abssq;
            
            mint A = mint(X[i]*X[i] - Y[i]*Y[i]) * invabssq;
            mint B = mint(2 * X[i] * Y[i]) * invabssq;
            ans -= 2 * (A * t1 + B * t2);
            t1 += A;
            t2 += B;
        }
        
        cout << ans.val() << '\n';
    }
}