[Serializable]
    class DistArr
    {
        [Serializable]
        class Pair
        {
            public byte first;
            public byte second;
        }

        private Dictionary<int, Pair> distArr;
        public DistArr(byte[] a, byte[] b)
        {
            for (int i = 0; i < a.Length; i++)
            {
                if (a[i] != b[i])
                {
                    distArr.Add(i, new Pair
                                       {
                                           first = a[i],
                                           second = b[i]
                                       });
                }
            }
        }
    }