#include <bits/stdc++.h>
using namespace std;

long long Solve() {
  int n;
  scanf("%d", &n);
  vector<int> x(n), y(n);
  for (int i = 0; i < n; ++i)
    scanf("%d %d", &x[i], &y[i]);
  
  long long ans = 0;
  for (int i = 0; i < n; ++i) {
    unordered_map<int,int> dist_cnt;
    for (int j = 0; j < n; ++j) {
      int dx = x[i] - x[j], dy = y[i] - y[j];
      ++dist_cnt[dx*dx + dy*dy];
    }
    for (const auto& p : dist_cnt) {
      ans += p.second * (p.second-1) / 2;
    }
  } 
  return ans;
}

int main() {
  int ntests;
  scanf("%d", &ntests);
  for (int nt = 1; nt <= ntests; ++nt) {
    printf("Case #%d: %lld\n", nt, Solve());
  }
  return 0;
}