import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        long[] dp = new long[n+1];
        for(int i = 0; i < m; i++){
            int a = scanner.nextInt();
            dp[a] = -1;
        }
        dp[0] = 1;
        if(dp[1] == 0){
            dp[1] = 1;
        }else{
            dp[1] = 0;
        }
        for(int i = 2; i <= n; i++){
            if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            }
        }
        System.out.println(dp[n]);
    }
}
 import java.util.*; util.* java class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        long[] dp = new long[n+1];
        for(int i = 0; i < m; i++){
            int a = scanner.nextInt();
            dp[a] = -1;
        }
        dp[0] = 1;
        if(dp[1] == 0){
            dp[1] = 1;
        }else{
            dp[1] = 0;
        }
        for(int i = 2; i <= n; i++){
            if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            }
        }
        System.out.println(dp[n]);
    }
} Main public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        long[] dp = new long[n+1];
        for(int i = 0; i < m; i++){
            int a = scanner.nextInt();
            dp[a] = -1;
        }
        dp[0] = 1;
        if(dp[1] == 0){
            dp[1] = 1;
        }else{
            dp[1] = 0;
        }
        for(int i = 2; i <= n; i++){
            if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            }
        }
        System.out.println(dp[n]);
    } main {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        long[] dp = new long[n+1];
        for(int i = 0; i < m; i++){
            int a = scanner.nextInt();
            dp[a] = -1;
        }
        dp[0] = 1;
        if(dp[1] == 0){
            dp[1] = 1;
        }else{
            dp[1] = 0;
        }
        for(int i = 2; i <= n; i++){
            if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            }
        }
        System.out.println(dp[n]);
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int n = scanner.nextInt(); n scanner.nextInt() scanner.nextInt scanner int m = scanner.nextInt(); m scanner.nextInt() scanner.nextInt scanner long[] dp = new long[n+1]; dp new long[n+1] n+1 n 1 for(int i = 0; i < m; i++){
            int a = scanner.nextInt();
            dp[a] = -1;
        } int i = 0; int i = 0; i 0 i < m i m i++ i++ i {
            int a = scanner.nextInt();
            dp[a] = -1;
        } {
            int a = scanner.nextInt();
            dp[a] = -1;
        } int a = scanner.nextInt(); a scanner.nextInt() scanner.nextInt scanner dp[a] = -1 dp[a] dp a -1 1 dp[0] = 1 dp[0] dp 0 1 if(dp[1] == 0){
            dp[1] = 1;
        }else{
            dp[1] = 0;
        } dp[1] == 0 dp[1] dp 1 0 {
            dp[1] = 1;
        } dp[1] = 1 dp[1] dp 1 1 {
            dp[1] = 0;
        } dp[1] = 0 dp[1] dp 1 0 for(int i = 2; i <= n; i++){
            if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            }
        } int i = 2; int i = 2; i 2 i <= n i n i++ i++ i {
            if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            }
        } {
            if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            }
        } if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            } dp[i] >= 0 dp[i] dp i 0 {
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            } dp[i] = (dp[i-1] + dp[i-2])%1000000007 dp[i] dp i (dp[i-1] + dp[i-2])%1000000007 (dp[i-1] + dp[i-2]) dp[i-1] dp i-1 i 1 dp[i-2] dp i-2 i 2 1000000007 {
                dp[i] = 0;
            } dp[i] = 0 dp[i] dp i 0 System.out.println(dp[n]) System.out.println System.out System System.out dp[n] dp n String[] args args
import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        long[] dp = new long[n+1];
        for(int i = 0; i < m; i++){
            int a = scanner.nextInt();
            dp[a] = -1;
        }
        dp[0] = 1;
        if(dp[1] == 0){
            dp[1] = 1;
        }else{
            dp[1] = 0;
        }
        for(int i = 2; i <= n; i++){
            if(dp[i] >= 0){
                dp[i] = (dp[i-1] + dp[i-2])%1000000007;
            }else{
                dp[i] = 0;
            }
        }
        System.out.println(dp[n]);
    }
}

