using System;
using System.Linq;
using System.Collections.Generic;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] NM = Console.ReadLine().Split(' ');
            int N = int.Parse(NM[0]);
            int M = int.Parse(NM[1]);
            int[] step_list = new int[N];
            int[] obstacles = new int[M];
            for(int i = 0; i < M; i++)
            {
                int ind = int.Parse(Console.ReadLine());
                step_list[ind] = 1;
                obstacles[i] = ind;
            }
            for (int i = 0; i < N-1; i++)
            {
                // Check for 2x damaged step first
                if (step_list[i] == 1 && step_list[i+1] == 1)
                {
                    // Game over. set 0
                    Console.WriteLine("0");
                    return;
                }
            }
            long cases = 1;
            for (int i = 0; i < M; i++)
            {
                int diff = 0;
                // Calc step count diff between obstacles
                switch (i)
                {
                    case 0:
                        diff = obstacles[i];
                        break;
                    default:
                        diff = obstacles[i] - obstacles[i - 1];
                        break;
                }
                // Calc step types (fibonacci)
                long[] fib_array = new long[] { 0, 1 };
                long fib = 1;
                for (int j = 0; j < diff - 1; j++)
                {
                    fib = fib_array[0] + fib_array[1];
                    fib_array[0] = fib_array[1];
                    fib_array[1] = fib;
                }
                cases *= fib % 1000000007;
            }
            // last 1 pos
            int diff_last = N - obstacles[M - 1];
            // Calc step types (fibonacci)
            long[] fib_array_last = new long[] { 0, 1 };
            long fib_last = 1;
            for (int j = 0; j < diff_last - 1; j++)
            {
                fib_last = fib_array_last[0] + fib_array_last[1];
                fib_array_last[0] = fib_array_last[1];
                fib_array_last[1] = fib_last;
            }
            cases *= fib_last % 1000000007;


            Console.WriteLine((cases%1000000007).ToString());
        }
    }
}