#include<bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define ll long long int
const ll N = 100+5 , INF = 1e18 , MOD = 1e9+7;
void solve(){
ll n;
cin >> n;
unordered_map<ll,ll> x,y;
vector<pair<ll,ll>> a(n+5);
for(ll i = 1; i <= n; i++){
cin >> a[i].first >> a[i].second;
x[a[i].first]++;
y[a[i].second]++;
}
ll cnt = 0;
for(ll i = 1; i <= n; i++) cnt += (x[a[i].first]-1)*(y[a[i].second]-1);
cout << cnt;
}
int main(){
fast;
ll tc = 1;
// cin >> tc;
while(tc--) solve();
return 0;
}
