import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int X = sc.nextInt();
        int N = sc.nextInt();
      	if(N==0){
          System.out.println(String.valueOf(X));
          return;
        }
      
      List<Integer> forbits = new ArrayList<Integer>();
      for(int i=0;i<N;i++){
          forbits.add(sc.nextInt());
        }
      
      int diff = 0;
      int answer = 0;
      while(true){
        if(!forbits.contains(X-diff)){
          answer = X-diff;
          break;
        } else if(!forbits.contains(X+diff)){
          answer = X+diff;
          break;
        }
        diff++;
      }
      
      System.out.println(String.valueOf(answer));
    }
}
/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