#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define N int(1e6)
using namespace std;
unordered_map<ll,ll>cnt,cnt1;
ll n,ans;
pair<ll,ll>a[N+10];
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i].fi>>a[i].se;
        cnt[a[i].fi]++;
        cnt1[a[i].se]++;
    }
    for(int i=1;i<=n;i++)
    {
        ll x1=cnt[a[i].fi]-1;
        ll y1=cnt1[a[i].se]-1;
        //cout<<a[i].fi<<" "<<a[i].se<<" "<<x1<<" "<<y1<<'\n';
        ans+=x1*y1;
    }
    cout<<ans;


    return 0;
}