using System;
public class Program
{
    static void Main()
    {

    string[] data = Console.ReadLine().Split();
    int[] days = new int[3];
    int answer = 0;
    
    for(int i=0;i<3;i++)
        days[i]=int.Parse(data[i]);
        
    for(int i=1; i<days[2];i++)
        if(i!=days[0] || i!=days[1])
            answer += 1;
            
    Console.Write(answer);

        
    }
}