#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[n], b[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  int cnt = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (a[i] == b[j]) cnt++;
    }
  }
  cout << cnt << endl;
  return 0;
}
