import java.io.*;
import java.util.*;

public class Main {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }

    static FastReader s = new FastReader();
    static PrintWriter out = new PrintWriter(System.out);

    private static int[] rai(int n) {
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = s.nextInt();
        }
        return arr;
    }

    private static int[][] rai(int n, int m) {
        int[][] arr = new int[n][m];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                arr[i][j] = s.nextInt();
            }
        }
        return arr;
    }

    private static long[] ral(int n) {
        long[] arr = new long[n];
        for (int i = 0; i < n; i++) {
            arr[i] = s.nextLong();
        }
        return arr;
    }

    private static long[][] ral(int n, int m) {
        long[][] arr = new long[n][m];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                arr[i][j] = s.nextLong();
            }
        }
        return arr;
    }

    private static int ri() {
        return s.nextInt();
    }

    private static long rl() {
        return s.nextLong();
    }

    private static String rs() {
        return s.next();
    }

    static boolean isPrime(int val)
    {
        int flag=0;
        for(int i=2;i<=Math.sqrt(val);i++)
        {
            if(val%i==0)
            {
                flag=1;
                break;
            }
        }
        return flag==0;
    }
    public static void main(String[] args) throws IOException {
        StringBuilder ans = new StringBuilder();
//        int t=ri();
        int t=1;
        while (t-- > 0)
        {
            int x=ri();
            int n=ri();
            int[] arr=rai(n);
            HashSet<Integer> set=new HashSet<>();
            for(int i:arr)
            {
                set.add(i);
            }
            int val=0;
            while(true)
            {
                int v1=x-val;
                if(!set.contains(v1))
                {
                    ans.append(v1).append("\n");
                    break;
                }
                int v2=x+val;
                if(!set.contains(v2))
                {
                    ans.append(v2).append("\n");
                    break;
                }
                val++;
            }
        }
        out.print(ans.toString());
        out.flush();

    }
}
//9999991


Measured memory_bytes: 25392