import sys
input = sys.stdin.readline

mod=998244353

T=int(input())
for tests in range(T):
    N=int(input())
    A=[list(map(int,input().split())) for i in range(N)]

    X=0
    Y=0

    Z0=0
    Z1=0

    W0=0
    W1=0
    
    for x,y in A:
        X+=x*x+y*y
        Y+=pow(x*x+y*y,mod-2,mod)

        Z0=Z0+(x*x-y*y)*pow(x*x+y*y,mod-2,mod)
        Z1=Z1+(2*x*y)*pow(x*x+y*y,mod-2,mod)
        
        W0=W0+(x*x-y*y)*pow(x*x+y*y,mod-2,mod)
        W1=W1+(-2*x*y)*pow(x*x+y*y,mod-2,mod)

    #print(X%mod,Y%mod,Z0,Z1,W0,W1)

    print((X*Y-(Z0*W0-Z1*W1))%mod)