using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var L = int.Parse(line[0]);
        var r = int.Parse(line[1]);
        var m = int.Parse(line[2]);
        var ans = Min(m, r - L + 1);
        Console.WriteLine(ans);
    }
}