import java.util.*;

public class Exercise94{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    int[] cards = new int[n];
    for(int i = 0; i < n; i++){
      cards[i] = i + 1;
    }
    int m = sc.nextInt();
    for(int i = 0; i < m; i++){
      int x = sc.nextInt() - 1;
      int y = cards[x];
      for(int j = x - 1; j >= 0; j--){
        cards[j + 1] = cards[j];
      }
      cards[0] = y;
    }
    System.out.println(cards[0]);
  }
}