#include <bits/stdc++.h>
using namespace std;
const int inf = (1 << 30) - 1;
const long long linf = (1ll << 62) - 1;
int GLL(long long& x) { return scanf("%lld", &x); }
int GI(int& x) { return scanf("%d", &x); }
void IO() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin.exceptions(ios::badbit | ios::failbit);
}
void file() {
  freopen("mountains.in", "r", stdin);
  freopen("mountains.out", "w", stdout);
}
const int N = 1e5 + 7, M = 2 * N;
int to[M], nxt[M], head[N], ne, visited[N], vid;
int n, m;
void init() {
  memset(head, -1, n * sizeof(head[0]));
  ne = 0;
}
void addEdge(int u, int v) {
  to[ne] = v;
  nxt[ne] = head[u];
  head[u] = ne++;
}
void BiEdge(int u, int v) {
  addEdge(u, v);
  addEdge(v, u);
}
void solve() {
  long long n;
  cin >> n;
  long long x, y;
  vector<pair<int, int>> vi(n);
  map<pair<long long, long long>, long long> mp;
  unordered_map<long long, long long> mpx;
  unordered_map<long long, long long> mpy;
  long long ans = 0;
  for (int i = 0; i < n; i++) {
    cin >> x >> y;
    ans += mpx[x]++;
    ans += mpy[y]++;
    ans -= mp[{x, y}]++;
  }
  cout << ans << endl;
}
int main() {
  IO();
  long long t = 1;
  solve();
}
