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();
		Integer[] p = new Integer[N];
		for (int i = 0; i < N; i++) {
			p[i] = sc.nextInt();
		}
		sc.close();

		// -1, +2, -3, +4という順番で調べていく
		int num = X;
		for (int i = 0; i <= 200; i++) {
			if (i % 2 == 1) {
				num = num - i;
			} else {
				num = num + i;
			}

			if (Arrays.asList(p).indexOf(num) == -1) {
				System.out.println(num);
				return;
			}
		}
	}
}

/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