Parallelogram

#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
void solve();

int main() {
    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

void solve() {
    int i,j;
    int n; cin >> n;
    vector<pair <long long , long long >> p ;
    map < pair <long long , long long >,long long> mp;
    set<pair<long double,long double>> st;
    for(i=0;i<n;i++){
        int a,b;
        cin>>a>>b;
        p.push_back({a,b});
    }
    for(i=0;i<n;i++){
        for(j=i+1;j<n;j++){
            pair<long double, long double> y={(p[i].first+p[j].first)/2.0,(p[i].second+p[j].second)/2.0  };
            mp[y]++;
            st.insert(y);
            cout<<"fj"<<endl;

        }
    }
    long long sum=0;
    for(auto it: st){
        sum += (mp[it] * (mp[it]+1))/2;
        cerr<<sum<<endl;
    }
    cout<<sum<<endl;
}