import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力値の取得
		int X = sc.nextInt();
		int N = sc.nextInt();
		
		if (N == 0) {
			System.out.println(X);
			sc.close();
			return;
		}
		
		Set<Integer> p = new HashSet<>();
		for (int i = 0; i < N; i++) {
			p.add(sc.nextInt());
		}
		
		// 結果の出力
		for (int i = 0; i <= 100; i++) {
			if (!p.contains(X - i)) {
				System.out.println(X - i);
				break;
			}
			else if (!p.contains(X + i)) {
				System.out.println(X + i);
				break;
			}
		}

		sc.close();
	}
}

/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