static void Main(string[] args)
{
int cases = int.Parse(Console.ReadLine());
List<string> list = new List<string>();
for (int i = 0; i < cases; i++)
{
string[] temp = Console.ReadLine().Split(' ');
if (!list.Contains(temp[0] + " " + temp[1]))
{
if (temp[0] != temp[1])
{
list.Add(temp[0] + " " + temp[1]);
}
}
}
Console.WriteLine(list.Count);
Console.ReadLine();
}