class Program
    {
        static void Main(string[] args)
        {

            int[] nm = Array.ConvertAll(Console.ReadLine().Split(' '), num => int.Parse(num));
            List<int> card = new List<int>();
            card = CardListCreation(nm[0],card);
            int[] shuffle = Array.ConvertAll(Console.ReadLine().Split(' '), num => int.Parse(num));
            for(int i = 0; i < nm[1]; i++)
            {
                card.Insert(0, card[shuffle[i]-1]);
                card.RemoveAt(shuffle[i]);
            }

            Console.WriteLine(card[0]);
        }

        private static List<int> CardListCreation(int v,List<int> card)
        {
            for(int i = 1; i <= v; i++)
            {
                card.Add(i);
            }
            return card;
        }
    }