using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        int[] NM = Console.ReadLine().Split(' ').Select(s => int.Parse(s)).ToArray();
        int[] A = Console.ReadLine().Split(' ').Select(s => int.Parse(s)).ToArray();

        List<int> cards = new List<int>();
        for (int i = 0; i < NM[0]; i++) { cards.Add(i + 1); }

        for (int i = 0; i < NM[1]; i++)
        {
            cards.Insert(0, cards[A[i]-1]);
            cards.RemoveAt(A[i]);
        }

        Console.WriteLine(cards[0]);
    }
}