using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AtCorder
{
	public class Program
	{
		const long MOD = 1000000007;
		static Dictionary<int, long> memo;
		static void Main(string[] args)
		{
			Scanner cin = new Scanner();
			int n = cin.Int();
			int m = cin.Int();
			memo = new Dictionary<int, long>();
			int[] a = new int[m];
			for (int i = 0; i < m; i++) {
				a[i] = cin.Int();
			}

			long ans = DFS(0, a, n);
			Console.WriteLine(ans);
		}
		
		public static long DFS(int n, int[] a, int max)
		{
			if (n >= max) {
				return 1;
			}

			if (memo.ContainsKey(n)) {
				return memo[n];
			}

			long ret = 0;
			if (a.Contains(n + 1) == false) {
				ret = (ret + DFS(n + 1, a, max)) % MOD;
			}

			if (n + 2 <= max && a.Contains(n + 2) == false) {
				ret = (ret + DFS(n + 2, a, max)) % MOD;
			}

			memo[n] = ret;

			return ret;
		}
	}

	public class Scanner
	{
		string[] s;
		int i;

		char[] cs = new char[] { ' ' };

		public Scanner()
		{
			s = new string[0];
			i = 0;
		}

		public string Next()
		{
			if (i < s.Length) return s[i++];
			string st = Console.ReadLine();
			while (st == "") st = Console.ReadLine();
			s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
			if (s.Length == 0) return Next();
			i = 0;
			return s[i++];
		}

		public int Int()
		{
			return int.Parse(Next());
		}
		public int[] ArrayInt(int N, int add = 0)
		{
			int[] Array = new int[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Int() + add;
			}
			return Array;
		}

		public long Long()
		{
			return long.Parse(Next());
		}

		public long[] ArrayLong(int N, long add = 0)
		{
			long[] Array = new long[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Long() + add;
			}
			return Array;
		}

		public double Double()
		{
			return double.Parse(Next());
		}


		public double[] ArrayDouble(int N, double add = 0)
		{
			double[] Array = new double[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Double() + add;
			}
			return Array;
		}
	}
}
