import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashSet;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] s = br.readLine().split(" ");
        int x = Integer.parseInt(s[0]);
        int n = Integer.parseInt(s[1]);
        if(n == 0) {
            System.out.print(x);
            return;
        }

        s = br.readLine().split(" ");
        HashSet<Integer> set = new HashSet<>();
        for(int i=0; i<n; i++)
            set.add(Integer.parseInt(s[i]));
        
        if(!set.contains(x)) {
            System.out.print(x);
            return;
        }
        int nearest = 1;
        while(true) {
            if(!set.contains(x-nearest)) {
                System.out.print(x-nearest);
                return;
            }

            if(!set.contains(x+nearest)) {
                System.out.print(x+nearest);
                return;
            }
            nearest++;
        }
    }
}
/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