import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskB {
        public void solve(int testNumber , InputReader in , PrintWriter out){
            int n = in.nextInt();
            int m = in.nextInt();
            int[] arr = new int[n+1];
            for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            }
           long[] dp = new long[n+1];
            dp[0] = 1;
            if (arr[1] == 0) dp[1] = 1;
            for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            }
            out.println(dp[n] %(1000000000+7));






        }
    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }

} import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.*; util.* java import java.io.IOException; IOException java.io import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.InputStream; InputStream java.io public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskB {
        public void solve(int testNumber , InputReader in , PrintWriter out){
            int n = in.nextInt();
            int m = in.nextInt();
            int[] arr = new int[n+1];
            for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            }
           long[] dp = new long[n+1];
            dp[0] = 1;
            if (arr[1] == 0) dp[1] = 1;
            for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            }
            out.println(dp[n] %(1000000000+7));






        }
    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }

} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) TaskB solver = new TaskB(); solver new TaskB() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class TaskB {
        public void solve(int testNumber , InputReader in , PrintWriter out){
            int n = in.nextInt();
            int m = in.nextInt();
            int[] arr = new int[n+1];
            for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            }
           long[] dp = new long[n+1];
            dp[0] = 1;
            if (arr[1] == 0) dp[1] = 1;
            for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            }
            out.println(dp[n] %(1000000000+7));






        }
    } TaskB public void solve(int testNumber , InputReader in , PrintWriter out){
            int n = in.nextInt();
            int m = in.nextInt();
            int[] arr = new int[n+1];
            for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            }
           long[] dp = new long[n+1];
            dp[0] = 1;
            if (arr[1] == 0) dp[1] = 1;
            for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            }
            out.println(dp[n] %(1000000000+7));






        } solve {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] arr = new int[n+1];
            for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            }
           long[] dp = new long[n+1];
            dp[0] = 1;
            if (arr[1] == 0) dp[1] = 1;
            for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            }
            out.println(dp[n] %(1000000000+7));






        } int n = in.nextInt(); n in.nextInt() in.nextInt in int m = in.nextInt(); m in.nextInt() in.nextInt in int[] arr = new int[n+1]; arr new int[n+1] n+1 n 1 for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            } int i = 0; int i = 0; i 0 i <m i m i++ i++ i {
                arr[in.nextInt()] = 1;
            } {
                arr[in.nextInt()] = 1;
            } arr[in.nextInt()] = 1 arr[in.nextInt()] arr in.nextInt() in.nextInt in 1 long[] dp = new long[n+1]; dp new long[n+1] n+1 n 1 dp[0] = 1 dp[0] dp 0 1 if (arr[1] == 0) dp[1] = 1; arr[1] == 0 arr[1] arr 1 0 dp[1] = 1 dp[1] dp 1 1 for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            } int i = 2 ; int i = 2 ; i 2 i <=n i n i++ i++ i {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            } {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            } dp[i] = dp[i-1]+dp[i-2] dp[i] dp i dp[i-1]+dp[i-2] dp[i-1] dp i-1 i 1 dp[i-2] dp i-2 i 2 dp[i]%=1000000000+7 dp[i] dp i 1000000000+7 1000000000 7 if (arr[i] == 1) dp[i] = 0; arr[i] == 1 arr[i] arr i 1 dp[i] = 0 dp[i] dp i 0 out.println(dp[n] %(1000000000+7)) out.println out dp[n] %(1000000000+7) dp[n] dp n (1000000000+7) 1000000000 7 int testNumber testNumber InputReader in in PrintWriter out out static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    } InputReader public BufferedReader reader; reader public StringTokenizer tokenizer; tokenizer public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } InputReader {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } next {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } IOException e {
                    throw new RuntimeException(e);
                } throw new RuntimeException(e); new RuntimeException(e) {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer public int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskB {
        public void solve(int testNumber , InputReader in , PrintWriter out){
            int n = in.nextInt();
            int m = in.nextInt();
            int[] arr = new int[n+1];
            for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            }
           long[] dp = new long[n+1];
            dp[0] = 1;
            if (arr[1] == 0) dp[1] = 1;
            for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            }
            out.println(dp[n] %(1000000000+7));






        }
    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }

} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskB {
        public void solve(int testNumber , InputReader in , PrintWriter out){
            int n = in.nextInt();
            int m = in.nextInt();
            int[] arr = new int[n+1];
            for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            }
           long[] dp = new long[n+1];
            dp[0] = 1;
            if (arr[1] == 0) dp[1] = 1;
            for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            }
            out.println(dp[n] %(1000000000+7));






        }
    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }

} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskB {
        public void solve(int testNumber , InputReader in , PrintWriter out){
            int n = in.nextInt();
            int m = in.nextInt();
            int[] arr = new int[n+1];
            for (int i = 0; i <m ; i++) {
                arr[in.nextInt()] = 1;
            }
           long[] dp = new long[n+1];
            dp[0] = 1;
            if (arr[1] == 0) dp[1] = 1;
            for (int i = 2 ; i <=n ; i++) {
                dp[i] = dp[i-1]+dp[i-2];
                dp[i]%=1000000000+7;
                if (arr[i] == 1) dp[i] = 0;
            }
            out.println(dp[n] %(1000000000+7));






        }
    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }

}