#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
constexpr int MOD=998244353;

namespace Lib{
  ll modpow(long long a,int n){
    long long ret=1,t=a;
    while(n>0){
      if(n&1)ret=ret*t%MOD;
      t=t*t%MOD;
      n/=2;
    }
    return ret;
  }
}

void solve();
int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int test_case;
  cin>>test_case;
  while (test_case--){
    solve();
  }
}
ll modinv(ll n){
  return Lib::modpow(n,MOD-2);
}
void solve(){
  int N;
  cin>>N;
  vector A(N,array<int,2>());
  for(auto &i:A)cin>>i[0]>>i[1];
  ll p2=0,Rs=0,Is=0;
  for(auto i:A){
    p2=(p2+i[0]*i[0]+i[1]*i[1])%MOD;
    Rs=(Rs+(i[0]*i[0]-i[1]*i[1])*modinv(i[0]*i[0]+i[1]*i[1]))%MOD;
    Is=(Is+2*i[0]*i[1]*modinv(i[0]*i[0]+i[1]*i[1]))%MOD;
  }
  ll ans=0;
  for(auto i:A){
    ll b=i[0]*i[0]+i[1]*i[1];
    ll pr=(i[0]*i[0]-i[1]*i[1])*modinv(b)%MOD,pi=(-2*i[0]*i[1])*modinv(b)%MOD;

    ans=(ans+p2*modinv(b)*2)%MOD;
    ans=(ans-Rs*pr*2+Is*pi*2)%MOD;
  }
  ans=(ans+MOD)%MOD;
  ans=(ans*((MOD+1)/2))%MOD;
  cout<<ans<<'\n';
}