#include <bits/stdc++.h>
#define ff first
#define ss second
using namespace std;
int main(){
ios::sync_with_stdio(0), cin.tie(0);
int n; cin >> n;
vector <pair<int , int>> v;
int t = n;
while(t--){
int x , y;
cin >> x >> y;
v.push_back({x , y});
}
int ans = 0;
for (int i = 0; i < n; i++){
for (int j = i + 1; j < n; j++){
for (int k = i +1; k < n; k++){
if((v[i].first != v[j].first and v[i].first !=
v[k].first) or (v[i].second != v[j].second and v[i].second !=
v[k].second))ans++;
}
}
}
cout << ans / 3<< endl;
return 0;
}
