#include <iostream>
#include <vector>

using namespace std;
struct Csillag
{
    int x, y;
};
int main()
{
    int n, i, db=0;
    cin>>n;
    vector<int> x(200001,0);
    vector<int> y(200001,0);
    Csillag a[n];
    for (i=0; i<n; i++)
    {

        cin>>a[i].x>>a[i].y;
        x[a[i].x]++;
        y[a[i].y]++;
    }

    for (i=0; i<n; i++)
    {
        if (((x[a[i].x]-1)>0)&&((y[a[i].y]-1)>0))
            db=db+(x[a[i].x]-1)*(y[a[i].y]-1);
    }
    cout<<db;
    return 0;
}