using System;
using System.Collections.Generic;//list用
using System.Text;//StringBuilder用
using System.Collections;
using System.Linq;
class Program
{
    static List<int> s = new List<int>();
    static decimal result;
static Hashtable ht=new Hashtable();
static StringBuilder sb = new StringBuilder();
static int N,M,K;
static long[,] table;
    static void Main()
    {
Read4();
      Read5();
Modular[] check=new Modular[N];
      for(int i=0;i<N;i++){check[i]=new Modular(0);}
      int j=0;
if(K>j && s[j]!=1){check[0]=1;}else{j++;}
if(N>1 && K>j && s[j]!=2){check[1]=check[0]+1;}else{j++;}
for(int i=2;i<N;i++){
check[i]=check[i-1]+check[i-2];
if(j<K && s[j]-1==i){check[i]=0;j++;}
}
      
      Console.WriteLine(((int)check[N-1]).ToString());

    }


    static void Read1()//1項
    {
        string tmp = Console.ReadLine();
        N = int.Parse(tmp);
    }
 
    static void Read2()//複数項（項目数Ｎ）
    {
        string[] tmp = Console.ReadLine().Split(' ');
        for (int i = 0; i < N; i++) { s.Add(int.Parse(tmp[i])); }
    }
    static void Read3()//1行複数項
   {
       string[] tmp = Console.ReadLine().Split(' ');
       for (int i = 0; i < tmp.Length; i++) { s.Add(int.Parse(tmp[i])); }
    }
    static void Read4()//NK１行
    {
        string[] tmp = Console.ReadLine().Split(' ');
       N = int.Parse(tmp[0]);
       K = int.Parse(tmp[1]);
    }
    static void Read5()//N行K項
    {
for(int i=0;i<K;i++){
        string tmp = Console.ReadLine();
        s.Add(int.Parse(tmp));
}
 
    }


}
class Modular
{
    private const int M = 1000000007;
    private long value;
    public Modular(long value) { this.value = value; }
    public static implicit operator Modular(long a)
    {
        var m = a % M;
        return new Modular((m < 0) ? m + M : m);
    }
    public static Modular operator +(Modular a, Modular b)
    {
        return a.value + b.value;
    }
    public static Modular operator -(Modular a, Modular b)
    {
        return a.value - b.value;
    }
    public static Modular operator *(Modular a, Modular b)
    {
        return a.value * b.value;
    }
    private static Modular Pow(Modular a, int n)
    {
        switch (n)
        {
        case 0:
            return 1;
        case 1:
            return a;
        default:
            var p = Pow(a, n / 2);
            return p * p * Pow(a, n % 2);
        }
    }
    public static Modular operator /(Modular a, Modular b)
    {
        return a * Pow(b, M - 2);
    }
    private static readonly List<int> facs = new List<int> { 1 };
    private static Modular Fac(int n)
    {
        for (int i = facs.Count; i <= n; ++i)
        {
            facs.Add((int)(Math.BigMul(facs.Last(), i) % M));
        }
        return facs[n];
    }
    public static Modular Ncr(int n, int r)
    {
        return (n < r)  ? 0
             : (n == r) ? 1
                        : Fac(n) / (Fac(r) * Fac(n - r));
    }
    public static explicit operator int(Modular a)
    {
        return (int)a.value;
    }
}
