#include <iostream>
#include <unordered_map>
#include <vector>
#include <algorithm>
#include <deque>
#include <set>
#include <utility>
#include <array>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,tune=native")
using namespace std;
#define ALL(x) x.begin(), x.end()
#define ShinLena cin.tie(nullptr)->sync_with_stdio(false);
using ll = long long;
#define N 300005
int n;
array<int, 2> a[N]; ll z;
unordered_map<int, int> b;
int main()
{
ShinLena;
for (int i = (cin >> n, 0); i < n; ++i) cin >> a[i][0] >> a[i][1], ++b[a[i][1]];
sort(a, a+n); n = unique(a, a+n) - a;
ll d=0;
for (int f, e = 0, i = 0, l = -1; i < n; ++i)
{
f = a[i][0] == l;
l += (a[i][0] - l) * !f, d *= f, e *= f;
z += d + (b[a[i][1]] - 1ll) * e;
++e, d += b[a[i][1]] - 1;
}
cout << z;
return 0;
}
