Imports System.Collections.Generic
Module Module1
    Sub Main()
        'let'
        Dim N As Long = CLng(Console.ReadLine())
        'var'
        Dim dic As New Dictionary(Of Long, Long)

        For i As Long = 0 To N - 1
            'let'
            Dim d As Long = CLng(Console.ReadLine())
            dic(d) = 1
        Next
        Console.WriteLine(dic.Count)
    End Sub
End Module
