import java.util.*;
public class Main {
    public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> List = new ArrayList<>();
        ArrayList<Long> L = new ArrayList<>();
        int N = sc.nextInt();
        int M = sc.nextInt();
        L.add((long)0);
        L.add((long)1);
        int num = 0;
        for(int i=0;i<M;i++) List.add(sc.nextInt());
        List.add(0);
        for(int i=2;i<N+2;i++){
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        }
        System.out.println(L.get(L.size()-1));
    }
} import java.util.*; util.* java public class Main {
    public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> List = new ArrayList<>();
        ArrayList<Long> L = new ArrayList<>();
        int N = sc.nextInt();
        int M = sc.nextInt();
        L.add((long)0);
        L.add((long)1);
        int num = 0;
        for(int i=0;i<M;i++) List.add(sc.nextInt());
        List.add(0);
        for(int i=2;i<N+2;i++){
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        }
        System.out.println(L.get(L.size()-1));
    }
} Main public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> List = new ArrayList<>();
        ArrayList<Long> L = new ArrayList<>();
        int N = sc.nextInt();
        int M = sc.nextInt();
        L.add((long)0);
        L.add((long)1);
        int num = 0;
        for(int i=0;i<M;i++) List.add(sc.nextInt());
        List.add(0);
        for(int i=2;i<N+2;i++){
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        }
        System.out.println(L.get(L.size()-1));
    } main {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> List = new ArrayList<>();
        ArrayList<Long> L = new ArrayList<>();
        int N = sc.nextInt();
        int M = sc.nextInt();
        L.add((long)0);
        L.add((long)1);
        int num = 0;
        for(int i=0;i<M;i++) List.add(sc.nextInt());
        List.add(0);
        for(int i=2;i<N+2;i++){
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        }
        System.out.println(L.get(L.size()-1));
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) ArrayList<Integer> List = new ArrayList<>(); List new ArrayList<>() ArrayList<Long> L = new ArrayList<>(); L new ArrayList<>() int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int M = sc.nextInt(); M sc.nextInt() sc.nextInt sc L.add((long)0) L.add L (long)0 L.add((long)1) L.add L (long)1 int num = 0; num 0 for(int i=0;i<M;i++) List.add(sc.nextInt()); int i=0; int i=0; i 0 i<M i M i++ i++ i List.add(sc.nextInt()); List.add(sc.nextInt()) List.add List sc.nextInt() sc.nextInt sc List.add(0) List.add List 0 for(int i=2;i<N+2;i++){
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        } int i=2; int i=2; i 2 i<N+2 i N+2 N 2 i++ i++ i {
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        } {
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        } if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            } List.get(num)+2!=i+1 List.get(num)+2 List.get(num) List.get List num 2 i+1 i 1 {
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            } long sec = (L.get(i-1)+L.get(i-2))%1000000007; sec (L.get(i-1)+L.get(i-2))%1000000007 (L.get(i-1)+L.get(i-2)) L.get(i-1) L.get L i-1 i 1 L.get(i-2) L.get L i-2 i 2 1000000007 L.add(sec) L.add L sec if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            } List.get(num)+2==i+1 List.get(num)+2 List.get(num) List.get List num 2 i+1 i 1 {
                long sec = 0;
                L.add(sec);
                num++;
            } long sec = 0; sec 0 L.add(sec) L.add L sec num++ num System.out.println(L.get(L.size()-1)) System.out.println System.out System System.out L.get(L.size()-1) L.get L L.size()-1 L.size() L.size L 1 String [] args args public class Main {
    public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> List = new ArrayList<>();
        ArrayList<Long> L = new ArrayList<>();
        int N = sc.nextInt();
        int M = sc.nextInt();
        L.add((long)0);
        L.add((long)1);
        int num = 0;
        for(int i=0;i<M;i++) List.add(sc.nextInt());
        List.add(0);
        for(int i=2;i<N+2;i++){
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        }
        System.out.println(L.get(L.size()-1));
    }
} public class Main {
    public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> List = new ArrayList<>();
        ArrayList<Long> L = new ArrayList<>();
        int N = sc.nextInt();
        int M = sc.nextInt();
        L.add((long)0);
        L.add((long)1);
        int num = 0;
        for(int i=0;i<M;i++) List.add(sc.nextInt());
        List.add(0);
        for(int i=2;i<N+2;i++){
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        }
        System.out.println(L.get(L.size()-1));
    }
} Main
import java.util.*;
public class Main {
    public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> List = new ArrayList<>();
        ArrayList<Long> L = new ArrayList<>();
        int N = sc.nextInt();
        int M = sc.nextInt();
        L.add((long)0);
        L.add((long)1);
        int num = 0;
        for(int i=0;i<M;i++) List.add(sc.nextInt());
        List.add(0);
        for(int i=2;i<N+2;i++){
            if(List.get(num)+2!=i+1){
                long sec = (L.get(i-1)+L.get(i-2))%1000000007;
                L.add(sec);
            }
            else if(List.get(num)+2==i+1){
                long sec = 0;
                L.add(sec);
                num++;
            }
        }
        System.out.println(L.get(L.size()-1));
    }
}