#include <bits/stdc++.h>
#define el '\n'
#define fi first
#define sc second
#define int ll
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
const int mod=1e9+7;
const int N=3e5+11;
int mp1[N],mp2[N], n, x[N],y[N], ans;
void sol()
{
memset(mp1, -1, sizeof mp1);
memset(mp2, -1, sizeof mp2);
cin >> n;
for(int i=1;i<=n; i++)
{
cin >> x[i] >> y[i];
mp1[x[i]]++;
mp2[y[i]]++;
}
for(int i=1; i<=n; i++) ans+=mp1[x[i]]*mp2[y[i]];
cout << ans;
}
signed main()
{
// freopen("divisor.INP", "r", stdin);
// freopen("divisor.OUT", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
int t=1;
//cin >> t;
while(t--)
{
sol();
}
}
