using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static string[] SList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => ReadLine()).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var s = SList(n);
        var set = new HashSet<string>();
        for (var i = 0; i < n; ++i) for (var j = 0; j < n; ++j)
        {
            if (i == j) continue;
            set.Add(s[i] + s[j]);
        }
        WriteLine(set.Count);
    }
}