int city[10000][10000] = { 0 };
int main()
{
	//freopen(".in","r", stdin);
	//freopen(".out", "w", stdout);
	int n;
	cin >> n;
	int sum = 0;
	while (n--)
	{
		string A, B;
		cin >> A >> B;
		int str1, str2;
		str1 = (A[0] - 'A') * 26 + A[1] - 'A';
		str2 = (B[0] - 'A') * 26 + B[1] - 'A';
		if (str1 == str2) { continue; }
		else {
			city[str1][str2] = 1;
			if (city[str2][str1] == 1)sum++;
		}
	}
	cout << sum << endl;
}