#include <stdio.h>

long long power_mod (long long a, long long b, long long mod_num) {
  long long ans = 1LL;
  
  if (b > 0LL) {
    ans = power_mod(a, b/2LL, mod_num);
    ans = (ans * ans) % mod_num;
    if (b%2LL == 1LL) {
      ans = (ans * (a % mod_num)) % mod_num;
    }
  }
  
  return ans;
}

int main () {
  int t = 0;
  int n = 0;
  long long x[300000] = {};
  long long y[300000] = {};
  
  int res = 0;
  
  long long mod_num = 998244353LL;
  
  res = scanf("%d", &t);
  while (t > 0) {
    long long ans = 0LL;
    long long acc[6] = {};
    res = scanf("%d", &n);
    for (int i = 0; i < n; i++) {
      res = scanf("%lld", x+i);
      res = scanf("%lld", y+i);
    }
    for (int i = n-1; i >= 0; i--) {
      long long tmp[6] = {};
      long long abs_sq = (x[i]*x[i]+y[i]*y[i])%mod_num;
      long long inv = power_mod(abs_sq, mod_num-2LL, mod_num);
      tmp[0] = inv;
      tmp[1] = abs_sq;
      tmp[2] = ((x[i]*x[i]+mod_num-(y[i]*y[i])%mod_num)*inv)%mod_num;
      tmp[3] = ((2LL*x[i]*y[i])*inv)%mod_num;
      tmp[4] = tmp[2];
      tmp[5] = (mod_num-tmp[3])%mod_num;
      ans += (tmp[0]*acc[1])%mod_num;
      ans += (tmp[1]*acc[0])%mod_num;
      ans += mod_num-(tmp[2]*acc[4])%mod_num;
      ans += (tmp[3]*acc[5])%mod_num;
      ans += mod_num-(tmp[4]*acc[2])%mod_num;
      ans += (tmp[5]*acc[3])%mod_num;
      for (int j = 0; j < 6; j++) {
        acc[j] += tmp[j];
        acc[j] %= mod_num;
      }
    }
    printf("%lld\n", ans%mod_num);
    t--;
  }
  
  return 0;
}