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

class Program
{
  
  public static int Main()
  {
    Scanner cin = new Scanner();
    int n = cin.nextInt(), m = cin.nextInt();
    List<int> list = new List<int>();
    for (int i = 1; i <= n; i++)
    {
      list.Add(i);
    }
    for (int i = 0; i < m; i++)
    {
      int a = cin.nextInt() - 1;
      int num = list[a];
      list.RemoveAt(a);
      list.Insert(0, num);
    }
    Console.WriteLine(list[0]);
    return 0;
  }
}

class Scanner {
  string[] s;
  int i;

  char[] cs = new char[] { ' ' };

  public Scanner() {
    s = new string[0];
    i = 0;
  }

  public string next() {
    if (i < s.Length) return s[i++];
    do {
      s = Console.ReadLine().Split(cs, StringSplitOptions.RemoveEmptyEntries);
    } while ((s.Length == 1 && s[0] == "") || s.Length == 0);
    i = 0;
    return s[i++];
  }

  public int nextInt() {
    return int.Parse(next());
  }

  public long nextLong() {
    return long.Parse(next());
  }

  public double nextDouble() {
    return double.Parse(next());
  }

}