using System.Numerics;

public class Program
{
    public static void Main()
    {
        //Biginteger num =BigInteger.Parse(Console.ReadLine() ?? string.Empty);
        string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string str = Console.ReadLine() ?? string.Empty;


        BigInteger ho1 =BigInteger.Parse(str[0]);
       BigInteger ho2 =BigInteger.Parse(str[1]);
       BigInteger final =BigInteger.Parse(str[2]);

        int count = 0;
        for (int i = 1;i<=final;i++)
        {
            if(i==ho1 || i ==ho2)
            {
                continue;
            }
            count++;
        }
        Console.WriteLine(count);

    }
}