import java.io.*;
import java.util.*;
public class Main{
    public static void main(String[] args) throws IOException{
        Reader r = new Reader();        
        int N, M;
        long C = 1000000007;
        {int[] a = r.ii(); N = a[0]; M = a[1];}
        int[] a = new int[M];
        for(int i = 0; i < M; i++){
            a[i] = r.i();
        }
        int[] broken = new int[N+1];
        for(int temp : a){
            broken[temp] = 1;
        }
        long[] f = new long[N+1];
        f[0] = 1;
        f[1] = broken[1] == 1 ? 0 : 1;        
        for(int i = 2; i <= N; i++){
            if(broken[i] == 0)
                f[i] = (f[i-1] + f[i-2])%C;
        }
        println(f[N]);
    }
    static void print(Object o){
        System.out.print(o.toString());
    }
    static void println(Object o){
        System.out.println(o.toString());
    }
    static int Int(String s){
        return Integer.parseInt(s);
    }
    static long Long(String s){
        return Long.parseLong(s);
    }
    static class Reader extends BufferedReader{
        Reader(){
            super(new InputStreamReader(System.in));
        }
        String s() throws IOException{
            return readLine();
        }
        String[] ss() throws IOException{
            return s().split(" ");
        }
        int i() throws IOException{
            return Int(s());
        }
        int[] ii() throws IOException{
            String[] ss = ss();
            int size = ss.length;
            int[] ii = new int[size];
            for(int j = 0; j < size; j++) ii[j] = Int(ss[j]);
            return ii;
        }
        long l() throws IOException{
            return Long(s());
        }
        long[] ll() throws IOException{
            String[] ss = ss();
            int size = ss.length;
            long[] ll = new long[size];
            for(int j = 0; j < size; j++) ll[j] = Long(ss[j]);            
            return ll;
        }
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz