#include <bits/stdc++.h>
using namespace std;
bool cmp(pair<int,int>&a,pair<int,int>&b)
{
if(a.first==b.first)return a.second<b.second;
return a.first<b.first;
}
int main()
{
int n,a,b;
cin>>n;
vector<pair<int,int>>v;
unordered_map<int,int>m,m1;
for(int i=0;i<n;i++)
{
cin>>a>>b;
v.push_back({a,b});
}
sort(v.begin(),v.end(),cmp);
int i=0;
long long int sum=0;
while(i<n)
{
pair<int,int>p=v[i];
int j=i+1;
int cnt=1;
while(j<n&&v[j].first==p.first)
{
cnt++;
j++;
}
while(i<j)
{
sum+=m[v[i].second];
sum+=m1[v[i].second]*(cnt-1);
m1[v[i].second]++;
m[v[i].second]+=(cnt-1);
i++;
}
}
cout<<sum;
return 0;
}
