#include <bits/stdc++.h>
#define fr first
#define se second
using namespace std;
const long long N = 3e5 + 7;
const long long inf = 1e9 + 7;
const long long mod = 1e9 + 7;
int n;
int a[N];
int b[N];
long long res;
map<int, int> x;
map<int, int> y;
int main()
{
/// freopen("input.txt", "r", stdin);
/// freopen("output.txt", "w", stdout);
ios_base::sync_with_stdio( false );
cin >> n;
for(int i = 1; i <= n; i ++){
cin >> a[i] >> b[i];
x[a[i]] ++, y[b[i]] ++;
}
for(int i = 1; i <= n; i ++){
res += (x[a[i]] - 1) * (y[b[i]] - 1);
}cout << res << "\n";
}
