// source problem :
#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define int long long
#define lb lower_bound
#define ub upper_bound
#define MASK(i) (1LL << (i))
const int inf = 1e18;
void ckmax(int& f, int s)
{
f = (f > s ? f : s);
}
void ckmin(int& f, int s)
{
f = (f < s ? f : s);
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<pair<int, int>> a(n);
map<int, int> mx, my;
for (auto &[x, y] : a) {
cin >> x >> y;
mx[x]++;
my[y]++;
}
int ans = 0;
for (auto [x, y] : a) {
mx[x]--;
my[y]--;
ans += mx[x] * my[y];
mx[x]++;
my[y]++;
}
cout << ans;
return 0;
}
