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

    namespace ConsoleApp86 {
        class Program {
            static void Main(string[] args) {
                var st = Console.ReadLine().Split().Select(int.Parse).ToArray();
                int N = st[0];
                int M = st[1];
                int mod = 1000000007;

                var a = new int[M + 3];
                a[0] = -1;
                a[1] = 0;
                a[2] = 0;
                for (int i = 1; i <= M; i++) {
                    a[i] = int.Parse(Console.ReadLine());
                }
                a[M + 1] = N + 1;

                var X = new int[N + 1];
                X[0] = 1;
                X[1] = 1;
                for (int i = 2; i < N; i++) {
                    X[i] = (X[i - 2] % mod + X[i - 1] % mod) % mod;
                }

                //Console.WriteLine("Xの配列は" + string.Join(" ", X));
                //Console.WriteLine("aの配列は" + string.Join(" ", a));

                long ans = 1;

                if (N == 1) {
                    Console.WriteLine(1);
                    return;
                }
                if (N == 2) {
                    if (M == 0) {
                        Console.WriteLine(2);
                        return;
                    } else if (M == 1) {
                        Console.WriteLine(1);
                        return;
                    } else {

                    }
                }

                for (int i = 1; i <= M + 1; i++) {
                    //Console.WriteLine("X[" + (a[i] - a[i - 1] - 1) + "] = " + X[a[i] - a[i - 1] - 1] + "を掛けました");

                    if (a[i] - a[i - 1] >= 2) {
                        ans *= X[a[i] - a[i - 1] - 2];
                        ans %= mod;
                    }
                
                    if (a[i] - a[i - 1] == 1) {
                        ans *= 0;
                        Console.WriteLine(0);
                        return;
                    }
                }

                Console.WriteLine(ans);
            }
        }
    }
