// In the name of GOD
#include <bits/stdc++.h>
using namespace std;
#define good exit(0);
#define nl endl
#define ios ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define sz(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define pb push_back
#define bb begin()
#define ee end()
#define ff first
#define ss second
#define ll long long
#define db double
#define pii pair<int, int>
const int N = 3e5 + 555;
int n;
map<int, int> m, k;
int a[N], b[N];
int main(){
ios
cin >> n;
for(int i = 1; i <= n; ++i){
cin >> a[i] >> b[i];
m[a[i]]++;
k[b[i]]++;
}
int ans = 0;
for(int i = 1; i <= n; ++i){
int q = m[a[i]] - 1;
int w = k[b[i]] - 1;
ans += (q * w);
}
cout << ans;
return 0;
}
