#include<algorithm>
#include<iostream>
#include<vector>
#include<string>
#include<random>
#include<cmath>
#include<stack>
#include<map>
#include <iomanip>
#include <queue>
#include <set>
using namespace std;
using ll = long long;
using ull = unsigned long long;
ll mod = 1e9 + 7;
ll pv(ll a, ll b) {
if (b == 0)return 1;
ll res = (pv(a, b / 2));
if (b % 2) {
return (((res * res) % mod) * (a % mod)) % mod;
}
else {
return (res * res) % mod;
}
}
void solve() {
ll n; cin >> n;
vector<ll>x(n), y(n);
map<ll, ll>mp, mp1;
for (ll i = 0; i < n; i++) {
cin >> x[i] >> y[i];
mp[x[i]]++;
mp1[y[i]]++;
}
ll ans = 0;
for (int i = 0; i < n; i++) {
ans += ((mp[x[i]] - 1) * (mp1[y[i]] - 1));
}
cout << ans << endl;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL); cin.tie(nullptr);
ll _ = 1;
//cin >> _;
while (_--)
{
solve();
}
}
