#include<bits/stdc++.h>
#define ll long long
#define endl "\n"
#define fi first
#define se second
#define pb push_back
#define pll pair<long long, long long>
using namespace std;
void solve(){
ll n;
cin >> n;
map<ll,ll> x;
map<ll,ll> y;
vector<pll> v;
for(int i=1;i<=n;i++){
ll a,b;
cin >> a >> b;
x[a]++;
y[b]++;
v.pb({a,b});
}
ll ans = 0;
for(auto i:v){
ans += (x[i.fi]-1) * (y[i.se]-1);
}
cout << ans << endl;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tc = 1;
// cin >> tc;
while(tc--){
solve();
}
}
