class Program
{
    static void Main(string[] args)
    {
        string[] input = Console.ReadLine()!.Split(' ');
        int holiday1 = int.Parse(input[0]);
        int holiday2 = int.Parse(input[1]);
        int now = int.Parse(input[2]);
        int count = 0;

        for (int i = 0; i < now; i++)
        {
            if (i != holiday1 || i != holiday2)
            {
                count++;
            }
        }

        Console.WriteLine(count - 1);
    }
}