#include <bits/stdc++.h>
using namespace std;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
#ifdef Local
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int n;
cin >> n;
long long ans = 0;
map<int,int> cnt;
vector<pair<int,int>> v;
for(int i=1;i<=n;i++){
int x,y;
cin >> x >> y;
cnt[y]++;
v.push_back({y,x});
}
map<int,int> mp;
for(auto u:v){
mp[u.second] += cnt[u.first] - 1;
}
sort(v.begin(),v.end());
reverse(v.begin(),v.end());
map<int,int> mp2;
for(auto u:v){
mp[u.second] -= cnt[u.first] - 1;
ans += mp[u.second] + mp2[u.second];
mp2[u.second] += cnt[u.first] - 1;
}
cout << ans;
}
