using System;

namespace HM
{
    class Program
    {
        static void Main(string[] args)
        {
            double[] arrValues = Array.ConvertAll<string, double>(Console.ReadLine().Split(new char[] { ' ' },
                                 StringSplitOptions.RemoveEmptyEntries), elem => { return System.Convert.ToDouble(elem); });

            double floor = arrValues[0];
            double down = arrValues[1];
            double up = arrValues[2];

            if (floor < 0 && (floor + (up - down)) >= 0)
                Console.WriteLine(floor + (up - down) + 1);
            else if (floor > 0 && (floor + (up - down)) <= 0)
                Console.WriteLine(floor + (up - down) - 1);
            else
                Console.WriteLine(floor + (up - down));
        }
    }
}