/*
ID: agageld1
LANG: C++17
TASK:
*/
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define N 400005
#define ff first
#define ss second
#define pb push_back
#define sz(s) (int)s.size()
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ll n, t;
pair <int,int> a[N];
map <int,int> vis,m;
int main () {
ios::sync_with_stdio(0);cin.tie(0);
cin >> n;
for(int i=1;i<=n;i++) {
cin >> a[i].ff >> a[i].ss;
vis[a[i].ff]++;
m[a[i].ss]++;
}
int ans = 0;
for(int i =1;i<=n;i++) {
ans += (vis[a[i].ff] - 1) * (m[a[i].ss] - 1);
}
cout << ans << '\n';
}
