import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int M = sc.nextInt();
    int[] card = new int[N];
    for(int i = 0; i < N; i++) {
      card[i] = i + 1;
    }
    for(int i = 0; i < M; i++) {
      int pos = sc.nextInt() - 1;
      int temp = card[pos];
      for(int j = pos; j > 0; j++) {
        card[j] = card[j - 1];
      }
      card[0] = temp;
    }
    System.out.println(card[0]);
  }
}