T = int(input())
mod = 998244353

for _ in range(T):
    N = int(input())
    x, y = [list(i) for i in zip(*[list(map(int, input().split())) for _ in range(N)])]
    A = [(xi*xi+yi*yi)%mod for xi, yi in zip(x, y)]
    B = [(xi*xi-yi*yi)%mod for xi, yi in zip(x, y)]
    C = [(2*xi*yi)%mod for xi, yi in zip(x, y)]

    D = [pow(a, mod-2, mod) for a in A]
    E = [b*b*d for b, d in zip(B, D)]
    F = [b*d for b, d in zip(B, D)]
    G = [c*c*d for c, d in zip(C, D)]
    H = [c*d for c, d in zip(C, D)]

    sd, se, sf, sg, sh = sum(D)%mod, sum(E)%mod, sum(F)%mod, sum(G)%mod, sum(H)%mod
    print((sd*se-sf*sf + sd*sg-sh*sh)%mod)