#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 100 + 2;
const int mod = 1e9 + 7;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n; cin >> n;
map<int, ll> X, Y;
vector<int> x(n), y(n);
for (int i = 0; i < n; i++) {
cin >> x[i] >> y[i];
X[x[i]]++; Y[y[i]]++;
}
ll ans = 0;
for (int i = 0; i < n; i++) {
ans += (ll)(X[x[i]] - 1) * (Y[y[i]] - 1);
}
cout << ans << en;
return 0;
}
