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();
      	int ps[] = new int[n];
      	int ans;
      	int istack;
      
      	for(int i = 0;i < n;i++){
          istack = sc.nextInt();
          if(istack < x) ps[i] = Math.abs(x-istack)*2;
          else ps[i] = Math.abs(x-istack)*2+1;
        }
      
      	Arrays.sort(ps);
      	ans = 1;
      	for(int i = 0;i < n;i++){
          if(ps[i] == ans) ans++;
          else break;
    	}
      	if(ans%2 == 0) x -= ans/2;
      	else x += ans/2;
            
      	System.out.println(x);
      
	}
}
/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