100from100

using System;

public class Program
{
    public static void Main()
    {
        var line = Console.ReadLine();
        var numbersAsString = line.Split(' ');
        var numbers = new long[numbersAsString.Length];
        for (int j = 0; j < numbersAsString.Length; j++)
        {
            numbers[j] = int.Parse(numbersAsString[j]);
        }

        var answer = SumOfDifferences(numbers);
        Console.WriteLine(answer);
    }

    private static long SumOfDifferences(long[] numbers)
    {
        long sum = 0;
        for (int i = 1; i < numbers.Length; i++)
        {
            long diff = Math.Abs(numbers[i] - numbers[i - 1]);
            if (diff % 2 == 0)
            {
                i++;
                sum += diff;
            }
        }

        return sum;
    }
}