#include "bits/stdc++.h"
using namespace std;
// Even though the previous solution is correct (https://oj.uz/submission/687487), We might need to hold our coordinates inside of a set rather than an array because there might be stars who have same coordinates.
map<int, long long> x_cnt;
map<int, long long> y_cnt;
int main()
{
int n;
cin >> n;
set< pair<int, int> > coords;
for(int i = 0; i < n; i++) {
pair<int, int> star;
cin >> star.first >> star.second;
x_cnt[star.first]++;
y_cnt[star.second]++;
coords.insert(star);
}
//sort(coords, coords + n);
long long ans = 0;
for(pair<int, int> star : coords)
{
ans += (x_cnt[star.first] - 1) * (y_cnt[star.second] - 1);
}
cout << ans << "\n";
}
