#include <iostream>
using namespace std;

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

struct C {
    mint real;
    mint imag;

    C() : real(0), imag(0) {}

    C(mint real, mint imag) : real(real), imag(imag) {}

    C operator+(const C &rhs) const {
        return C(real + rhs.real, imag + rhs.imag);
    }

    C operator-(const C &rhs) const {
        return C(real - rhs.real, imag - rhs.imag);
    }

    C operator*(const C &rhs) const {
        return C(real * rhs.real - imag * rhs.imag, real * rhs.imag + imag * rhs.real);
    }

    C operator/(const C &rhs) const {
        mint norm = rhs.real * rhs.real + rhs.imag * rhs.imag;
        mint real_ = real * rhs.real + imag * rhs.imag;
        mint imag_ = imag * rhs.real - real * rhs.imag;
        return C(real_ / norm, imag_ / norm);
    }

    C conj() const {
        return C(real, -imag);
    }
};

// i != j |zi|^2 / |zj|^2 - (zi / zi*) (zj* / zj)

int main() {

    int T;
    cin >> T;
    while (T--) {
        int N;
        cin >> N;

        C sum_of_l2;
        C sum_of_inv_of_l2;
        C sum_of_z_div_z_conj;
        C sum_of_z_conj_div_z;
        while (N--) {
            int x, y;
            cin >> x >> y;
            C z(x, y);
            sum_of_l2 = sum_of_l2 + z * z.conj();
            sum_of_inv_of_l2 = sum_of_inv_of_l2 + C(1, 0) / (z * z.conj());

            sum_of_z_div_z_conj = sum_of_z_div_z_conj + z / z.conj();
            sum_of_z_conj_div_z = sum_of_z_conj_div_z + z.conj() / z;
        }

        cout << (sum_of_l2 * sum_of_inv_of_l2 - sum_of_z_div_z_conj * sum_of_z_conj_div_z).real.val() << '\n';
    }
}