using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;
using System.Text;

public class Program
{

    public void Proc()
    {
        int[] inpt = Reader.ReadLine().Split(' ').Select(a => int.Parse(a)).ToArray();
        decimal mul = GetD(-1000000, 1000000, inpt);
        decimal d = inpt[2] - (inpt[1] * mul);
        decimal ans = Math.Round(inpt[2] * mul + d, 0, MidpointRounding.AwayFromZero);
        Console.WriteLine(ans.ToString("#0"));

    }

    private decimal GetD(decimal min, decimal max, int[] nums) {
        if(max-min<0.000000001m) {
            if(GetDiff(max,nums)==0) {
                return max;
            } else {
                return min;
            }
        }

        decimal mid1 = min + (max - min) / 3;
        decimal mid2 = min + (max - min) * 2 / 3;

        decimal[] vals = new decimal[4];
        vals[0] = GetDiff(min, nums);
        vals[1] = GetDiff(mid1, nums);
        vals[2] = GetDiff(mid2, nums);
        vals[3] = GetDiff(max, nums);
        decimal minVals = vals.Min();
        if(vals[0]==minVals) {
            return GetD(min, mid1, nums);
        }
        if(vals[1] == minVals) {
            return GetD(min, mid2, nums);
        }
        if(vals[2] == minVals) {
            return GetD(mid1, max, nums);
        }
        return GetD(mid2, max, nums);
    }

    private decimal GetDiff(decimal mul, int[] nums) {
        decimal tmp = nums[1] - (nums[0] * mul);
        return Math.Abs(nums[2] - (nums[1] * mul + tmp));
    }

    public class Reader
	{
		private static StringReader sr;
		public static bool IsDebug = false;
		public static string ReadLine()
		{
			if (IsDebug)
			{
				if (sr == null)
				{
					sr = new StringReader(InputText.Trim());
				}
				return sr.ReadLine();
			}
			else
			{
				return Console.ReadLine();
			}
		}
		private static string InputText = @"




-100000 -99999 100000




";
	}

	public static void Main(string[] args)
	{
#if DEBUG
		Reader.IsDebug = true;
#endif
		Program prg = new Program();
		prg.Proc();
	}
}