import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt(), N = sc.nextInt(), minDiff = X, pNot[] = new int[102], ans = 0;
		for (int i = 0; i <= 101; i++)
			pNot[i] = 1;
		for (int i = 0; i < N; i++)
			pNot[sc.nextInt()] = 0;
		for (int i = 0; i <= 101; i++)
			if (pNot[i] == 1)
				if (minDiff > Math.abs(X - i)) {
					minDiff = Math.abs(X - i);
					ans = i;
				}
		System.out.println(ans);
	}

}

/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