#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ar array
#define fr first
#define sc second
#define vec vector
#define ret return
#define ins insert
#define mk make_pair
#define pb push_back
#define pf push_front
#define pob pop_back
#define pof pop_back
#define int long long
#define pii pair<int,int>
#define all(s) s.begin(), s.end()
#define allr(s) s.rbegin(), s.rend()
#define NeedForSpeed ios::sync_with_stdio(0),cin.tie(0);
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
const int N=1e6+12,INF=1e9,mod = 1e9+7;
bool iswowel(char n){ n = toupper(n); if(n == 'A' || n == 'O' || n == 'U' || n == 'E' || n == 'I') return true; else return false;}
int n,m,k,x,y,l,r,o,ans,res,ok,mx,mn = INF;
int a[N],b[N],c[N];
main(){
NeedForSpeed
cin>>n;
map<int,int>mpx, mpy;
for(int i=1; i<=n; i++){
cin>>a[i]>>b[i];
mpx[a[i]]++;
mpy[b[i]]++;
}
for(int i=1; i<=n; i++){
mpx[a[i]]--;
mpy[b[i]]--;
res += (mpx[a[i]]*mpy[b[i]]);
mpx[a[i]]++;
mpy[b[i]]++;
}
cout<<res;
}
