#include <cstdio>
#include <iostream>
#include <cmath>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <cstring>
#include <algorithm>
#define sc scanf
#define pr printf
#define pb push_back
#define mp std::make_pair
#define fr first
#define se second
#define sqr(i) ((i)*(i))
#define dist(i, j) (sqr(x[i]-x[j]) + sqr(y[i]-y[j]))

typedef std::pair<int, int> pii;
typedef std::pair<double, double> pdd;

const int MN = 300010;
const int M = 1 << 30;
const long long MAX_LONG = std::numeric_limits<long long>::max();
const int MAX_INT = std::numeric_limits<int>::max();
const int MIN_INT = std::numeric_limits<int>::min();

using namespace std;

pair<int, int> p[MN];

map<int, int>mx;
map<int, int>my;
set<int> sx;
set<int> sy;

int main() {
    //freopen("in.txt", "r", stdin); freopen("out.txt", "w", stdout);
    //freopen("spantree2.in", "r", stdin); freopen("spantree2.out", "w", stdout);
    int n;
    sc("%d", &n);
    for (int i = 0; i < n; i++) {
        sc("%d%d", &p[i].fr, &p[i].se);
        mx[ p[i].fr ]++;
        my[ p[i].se ]++;
        sx.insert( p[i].fr );
        sy.insert( p[i].se );

    }

    sort(p, p + n);

    long long ans = 0;

    for(auto a : sx) {
        long long cnt = mx[a];
        ans += (cnt * (cnt - 1)) / 2;
    }

    for(auto a : sy) {
        long long cnt = my[a];
        ans += (cnt * (cnt - 1)) / 2;
    }

    for (int i = 0; i < n; ) {
        int j = i;
        while (j < n && p[i] == p[j]) j++;

        long long cnt = j - i;

        ans -= cnt * (cnt - 1) / 2;

        i = j;
    }

    cout << ans << endl;
    return 0;
}