#include <map>
#include <iostream>
using namespace std;
struct point {
int64_t x, y;
};
map < int64_t, int64_t > ox;
map < int64_t, int64_t > oy;
//ifstream cin("triangles.in");
//ofstream cout("triangles.out");
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
point a[n];
for (int i = 0; i < n; i++) {
cin >> a[i].x >> a[i].y;
ox[a[i].x]++;
oy[a[i].y]++;
}
int64_t res = 0;
for (int i = 0; i < n; i++) {
res += (ox[a[i].x] - 1) * (ox[a[i].y] - 1);
}
cout << res << '\n';
return 0;
}
