#int(input())
#map(int, input().split())
#list(map(int, input().split()))

T = int(input())
n = [0] * T
X = [0] * T
for i in range(T):
    n[i] = int(input())
    y = [0] * n[i]
    for j in range(n[i]):
        y[j] = list(map(int, input().split()))
    X[i] = y
mod = 998244353

b = []
for k in range(T):
    # k = 1
    N = n[k]
    x = X[k]

    norm = [0] * N
    for i in range(N):
        norm[i] = x[i][0] ** 2 + x[i][1] ** 2
    norminv = [0] * N
    for i in range(N):
        norminv[i] = pow(norm[i], mod-2, mod)

    def f(x, y):
        re = x[0] * y[0] - x[1] * y[1]
        im = x[1] * y[0] + x[0] * y[1]
        return [re%mod, im%mod]

    s0 = [0, 0]
    for i in range(N):
        a = f(x[i], x[i])
        # print(x[i], a)
        for j in range(2):
            s0[j] = (s0[j] + a[j] * norminv[i]) % mod

    s1 = [0, 0]
    for i in range(N):
        y = [x[i][0], -x[i][1]]
        a = f(y, y)
        # print(y, a)

        for j in range(2):
            s1[j] = (s1[j] + a[j] * norminv[i]) % mod

    u0 = 0
    u1 = 0
    for i in range(N):
        u0 = (u0 + norm[i]) % mod
        u1 = (u1 + norminv[i]) % mod

    ans = 0
    ans = (ans + u0*u1) % mod
    ans = (ans - (s0[0]*s1[0] - s0[1]*s1[1])) % mod
    # ans = (ans * pow(2, mod-2, mod)) % mod

    # print(u0, u1)
    # print(s0, s1)
    b.append(ans)

for x in b:
    print(x)