#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define fi first
#define se second
#define ll long long
using namespace std;
const int N = 1e6 + 7;
const int mod = 1e9 + 7;
void solve()
{
int n;
map < int , ll > m,mm;
cin >> n;
ll ans = 0;
vector < int > x(n);
vector < int > y(n);
for( int i = 0; i < n; i++ ){
cin >> x[i] >> y[i];
m[x[i]]++ , mm[y[i]]++;
}
for( int i = 0; i < n; i++ ){
ans += (m[x[i]] - 1) * 1ll * (mm[y[i]] - 1);
}
cout << ans;
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
//freopen( "input.txt" , "r" , stdin );
//freopen( "output.txt" , "w" , stdout );
int t = 1;//cin >> t;
while( t-- ){
solve();
}
}