#include <iostream>

using namespace std;

int main()
{
    int n, c = 0;
    cin >> n;
    int *a = new int[n];
    int *b = new int[n];
    for (int i = 0; i < n; i++)
    {
        cin >> a[i] >> b[i];
    }
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            if (a[i] == b[j])
            {
                c++;
            }
        }
    }
    cout << c;
    delete[] a;
    a = NULL;
    delete[] b;
    b = NULL;
    return 0;
}