#include <bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC optimize ("fast-math")
#pragma GCC optimize ("unroll-loops")
using namespace std;
#define int long long
#define ll long long
#define all (x) begin(x), end (x)
#define xx first
#define yy second
using pii = pair <int, int>;
using tii = tuple <int, int, int>;
int n;
constexpr int NMAX = (int) 3e5;
int v[NMAX + 1], w[NMAX + 1];
map <int, int> frec, frec1;
int s;
signed main(void)
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin >> n;
for (int i = 1; i <= n; ++ i)
{
cin >> v[i] >> w[i];
frec[v[i]] ++;
frec1[w[i]] ++;
}
for (int i = 1; i <= n; ++ i)
{
s += (frec[v[i]] - 1) * (frec1[w[i]] - 1);
}
cout << s;
return 0 ^ 0;
}
