using System;
using System.Text;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using static System.Console;
using static System.Math;

namespace AtCorder
{
    public class Program
    {
        public static void Main(string[] args)
        {
            new Program().Solve(new ConsoleInput(Console.In, ' '));
        }

        public void Solve(ConsoleInput cin)
        {
            // 解答はココに書く
            var N = cin.ReadInt;
            var M = cin.ReadInt;
            var a = cin.ReadIntArray(M);
            var steps = new long[M + 1];
            var mod = (int)(Pow(10, 9) + 7);
            steps[0] = a[0] - 1;
            steps[M] = N - a[M - 1] - 1;
            long ans = 1L;
            for(int i = 1; i < M; i++)
            {
                if(a[i] - a[i - 1] - 2 < 0)
                {
                    WriteLine(0);
                    return;
                }
                steps[i] = a[i] - a[i - 1] - 2;
            }
            for(int i = 0; i <= M; i++)
            {
                if (steps[i] == 0 || steps[i] == 1) continue;
                ans *= fib(steps[i]);
                if (ans > mod)
                {
                    ans %= mod;
                }
            }
            WriteLine(ans);
        }
        public long fib(long x)
        {
            if(x == 1 || x == 0)
            {
                return 1;
            }
            return fib(x - 1) + fib(x - 2);
        }
    }

    public class ConsoleInput
    {
        private readonly System.IO.TextReader _stream;
        private char _separator = ' ';
        private Queue<string> inputStream;
        public ConsoleInput(System.IO.TextReader stream, char separator = ' ')
        {
            this._separator = separator;
            this._stream = stream;
            inputStream = new Queue<string>();
        }
        public string Read
        {
            get
            {
                if (inputStream.Count != 0) return inputStream.Dequeue();
                string[] tmp = _stream.ReadLine().Split(_separator);
                for (int i = 0; i < tmp.Length; ++i)
                    inputStream.Enqueue(tmp[i]);
                return inputStream.Dequeue();
            }
        }
        public string ReadLine { get { return _stream.ReadLine(); } }
        public int ReadInt { get { return int.Parse(Read); } }
        public long ReadLong { get { return long.Parse(Read); } }
        public double ReadDouble { get { return double.Parse(Read); } }
        public string[] ReadStrArray(long N) { var ret = new string[N]; for (long i = 0; i < N; ++i) ret[i] = Read; return ret; }
        public int[] ReadIntArray(long N) { var ret = new int[N]; for (long i = 0; i < N; ++i) ret[i] = ReadInt; return ret; }
        public long[] ReadLongArray(long N) { var ret = new long[N]; for (long i = 0; i < N; ++i) ret[i] = ReadLong; return ret; }
    }
}