import java.util.*;

public class Main{
  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);
    int X = sc.nextInt(), N=sc.nextInt(), min=1001, sa, ans=-100;
    String p[] = new String[N];
    for(int i=0; i<N; i++) {
      p[i] = sc.next();
	}
    
    for(int j=0; j<=101; j++) {
      if(!Arrays.asList(p).contains(String.valueOf(j))) {
        if(X>=j) {
          sa=X-j;
        } else {
          sa=j-X;
        }
        if(min>sa) {
          ans = j;
          min=sa;
        }
      }  
    }
    System.out.println(ans);
  }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz