#include<bits/stdc++.h>
#define int long long
#define INF 1e9
#define pb push_back
using namespace std;
void solve(){
int n; cin >> n;
vector<pair<int,int>> v;
map<int,int> x,y;
for(int i=0; i < n; i ++){
int q,w; cin >> q >> w;
v.pb({q,w});
x[q]++; y[w] ++;
// y[q]++; x[w] ++;
}
int s = 0;
for(auto i : v){
s += (x[i.first] - 1) * (y[i.second] - 1);
}
cout << s;
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
cout.tie(0)->sync_with_stdio(0);
int t;
t=1;
// cin >> t;
while(t--){
solve();
cout << '\n';
}
}
