#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, c = 0, temp;
  int h[101], g[101];
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> h[i] >> g[i];
  }
  for (int j = 0; j < n; j++) {
    temp = n - 1;
    while (temp > j) {
      if (h[j] == g[temp]) c++;
      if (h[temp] == g[j]) c++;
      temp--;
    }
  }
  cout << c;
  return 0;
}
