#include <bits/stdc++.h> //Andrei Alexandru a.k.a Sho10
#define ll long long
#define double long double
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#define all(a) (a).begin(), (a).end()
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define pi pair
#define rc(s) return cout<<s,0
#define endl '\n'
#define mod 1000007
#define PI 3.14159265359
#define MAXN 100005
#define INF 1000000005
#define LINF 1000000000000000005ll
#define CODE_START ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
ll n;
pair<ll,ll>a[300005];
map<ll,ll>x,y;
int32_t main(){
CODE_START
cin>>n;
for(ll i=1;i<=n;i++){
cin>>a[i].f>>a[i].s;
x[a[i].f]++;
y[a[i].s]++;
}
ll ans=0;
for(ll i=1;i<=n;i++)
{
ans+=(x[a[i].f]-1)*(y[a[i].s]-1);
}
cout<<ans<<endl;
}
