import java.util.Scanner;
  
  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];
          
          //カード配列作成
          for(int i=0; i<N; i++){
              Card[i] = i+1;
          }
          
          // シャッフル
          for(int j=0; j<M; j++){
              //K番目を１番目に
              int K = sc.nextInt();
              int temp = Card[K-1];
              
              //カードを後ろにずらす
              while (K-1>0){
                  Card[K-1] = Card[K-2];
                  K--;
              }
              Card[0]=temp;
          }
          System.out.println(Card[0]);
      }
  }