
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {
    static int toori = 0;

    public static void main(String[] args) {
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);

        int n = sc.nextInt();
        int m = sc.nextInt();

        boolean[] broken = new boolean[n + 1];

        for (int i = 0; i < m; i++) {
            broken[sc.nextInt()] = true;
        }

        long[] dp = new long[n + 2];
        dp[n + 1] = 0;
        dp[n] = 1;

        for (int i = n - 1; i >= 0; i--) {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        }

        out.println(dp[0]);

        out.flush();

    }

    static class Toi {
        public int x;
        public int y;

        public Toi(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }

            if (this == obj) {
                return true;
            }

            if (this.getClass() != obj.getClass()) {
                return false;
            }

            Toi toi = (Toi) obj;
            return x == toi.x && y == toi.y;
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.PrintWriter; PrintWriter java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    static int toori = 0;

    public static void main(String[] args) {
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);

        int n = sc.nextInt();
        int m = sc.nextInt();

        boolean[] broken = new boolean[n + 1];

        for (int i = 0; i < m; i++) {
            broken[sc.nextInt()] = true;
        }

        long[] dp = new long[n + 2];
        dp[n + 1] = 0;
        dp[n] = 1;

        for (int i = n - 1; i >= 0; i--) {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        }

        out.println(dp[0]);

        out.flush();

    }

    static class Toi {
        public int x;
        public int y;

        public Toi(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }

            if (this == obj) {
                return true;
            }

            if (this.getClass() != obj.getClass()) {
                return false;
            }

            Toi toi = (Toi) obj;
            return x == toi.x && y == toi.y;
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
} Main static int toori = 0; toori 0 public static void main(String[] args) {
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);

        int n = sc.nextInt();
        int m = sc.nextInt();

        boolean[] broken = new boolean[n + 1];

        for (int i = 0; i < m; i++) {
            broken[sc.nextInt()] = true;
        }

        long[] dp = new long[n + 2];
        dp[n + 1] = 0;
        dp[n] = 1;

        for (int i = n - 1; i >= 0; i--) {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        }

        out.println(dp[0]);

        out.flush();

    } main {
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);

        int n = sc.nextInt();
        int m = sc.nextInt();

        boolean[] broken = new boolean[n + 1];

        for (int i = 0; i < m; i++) {
            broken[sc.nextInt()] = true;
        }

        long[] dp = new long[n + 2];
        dp[n + 1] = 0;
        dp[n] = 1;

        for (int i = n - 1; i >= 0; i--) {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        }

        out.println(dp[0]);

        out.flush();

    } FastReader sc = new FastReader(); sc new FastReader() PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int m = sc.nextInt(); m sc.nextInt() sc.nextInt sc boolean[] broken = new boolean[n + 1]; broken new boolean[n + 1] n + 1 n 1 for (int i = 0; i < m; i++) {
            broken[sc.nextInt()] = true;
        } int i = 0; int i = 0; i 0 i < m i m i++ i++ i {
            broken[sc.nextInt()] = true;
        } {
            broken[sc.nextInt()] = true;
        } broken[sc.nextInt()] = true broken[sc.nextInt()] broken sc.nextInt() sc.nextInt sc true long[] dp = new long[n + 2]; dp new long[n + 2] n + 2 n 2 dp[n + 1] = 0 dp[n + 1] dp n + 1 n 1 0 dp[n] = 1 dp[n] dp n 1 for (int i = n - 1; i >= 0; i--) {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        } int i = n - 1; int i = n - 1; i n - 1 n 1 i >= 0 i 0 i-- i-- i {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        } {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        } if (broken[i]) {
                continue;
            } broken[i] broken i {
                continue;
            } continue; 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 out.println(dp[0]) out.println out dp[0] dp 0 out.flush() out.flush out String[] args args static class Toi {
        public int x;
        public int y;

        public Toi(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }

            if (this == obj) {
                return true;
            }

            if (this.getClass() != obj.getClass()) {
                return false;
            }

            Toi toi = (Toi) obj;
            return x == toi.x && y == toi.y;
        }
    } Toi public int x; x public int y; y public Toi(int x, int y) {
            this.x = x;
            this.y = y;
        } Toi {
            this.x = x;
            this.y = y;
        } this.x = x this.x this this.x x this.y = y this.y this this.y y int x x int y y @Override public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }

            if (this == obj) {
                return true;
            }

            if (this.getClass() != obj.getClass()) {
                return false;
            }

            Toi toi = (Toi) obj;
            return x == toi.x && y == toi.y;
        } equals {
            if (obj == null) {
                return false;
            }

            if (this == obj) {
                return true;
            }

            if (this.getClass() != obj.getClass()) {
                return false;
            }

            Toi toi = (Toi) obj;
            return x == toi.x && y == toi.y;
        } if (obj == null) {
                return false;
            } obj == null obj null {
                return false;
            } return false; false if (this == obj) {
                return true;
            } this == obj this obj {
                return true;
            } return true; true if (this.getClass() != obj.getClass()) {
                return false;
            } this.getClass() != obj.getClass() this.getClass() this.getClass this obj.getClass() obj.getClass obj {
                return false;
            } return false; false Toi toi = (Toi) obj; toi (Toi) obj return x == toi.x && y == toi.y; x == toi.x && y == toi.y x == toi.x x toi.x toi toi.x y == toi.y y toi.y toi toi.y Object obj obj static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        } FastReader {
            br = new BufferedReader(new InputStreamReader(System.in));
        } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } next {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } IOException e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    st = new StringTokenizer(br.readLine());
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() {
            return Double.parseDouble(next());
        } nextDouble {
            return Double.parseDouble(next());
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        } nextLine {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        } String str = ""; str "" try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                str = br.readLine();
            } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
    static int toori = 0;

    public static void main(String[] args) {
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);

        int n = sc.nextInt();
        int m = sc.nextInt();

        boolean[] broken = new boolean[n + 1];

        for (int i = 0; i < m; i++) {
            broken[sc.nextInt()] = true;
        }

        long[] dp = new long[n + 2];
        dp[n + 1] = 0;
        dp[n] = 1;

        for (int i = n - 1; i >= 0; i--) {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        }

        out.println(dp[0]);

        out.flush();

    }

    static class Toi {
        public int x;
        public int y;

        public Toi(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }

            if (this == obj) {
                return true;
            }

            if (this.getClass() != obj.getClass()) {
                return false;
            }

            Toi toi = (Toi) obj;
            return x == toi.x && y == toi.y;
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
} public class Main {
    static int toori = 0;

    public static void main(String[] args) {
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);

        int n = sc.nextInt();
        int m = sc.nextInt();

        boolean[] broken = new boolean[n + 1];

        for (int i = 0; i < m; i++) {
            broken[sc.nextInt()] = true;
        }

        long[] dp = new long[n + 2];
        dp[n + 1] = 0;
        dp[n] = 1;

        for (int i = n - 1; i >= 0; i--) {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        }

        out.println(dp[0]);

        out.flush();

    }

    static class Toi {
        public int x;
        public int y;

        public Toi(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }

            if (this == obj) {
                return true;
            }

            if (this.getClass() != obj.getClass()) {
                return false;
            }

            Toi toi = (Toi) obj;
            return x == toi.x && y == toi.y;
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
} Main

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {
    static int toori = 0;

    public static void main(String[] args) {
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);

        int n = sc.nextInt();
        int m = sc.nextInt();

        boolean[] broken = new boolean[n + 1];

        for (int i = 0; i < m; i++) {
            broken[sc.nextInt()] = true;
        }

        long[] dp = new long[n + 2];
        dp[n + 1] = 0;
        dp[n] = 1;

        for (int i = n - 1; i >= 0; i--) {
            if (broken[i]) {
                continue;
            }
            dp[i] = (dp[i + 1] + dp[i + 2]) % 1000000007;
        }

        out.println(dp[0]);

        out.flush();

    }

    static class Toi {
        public int x;
        public int y;

        public Toi(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }

            if (this == obj) {
                return true;
            }

            if (this.getClass() != obj.getClass()) {
                return false;
            }

            Toi toi = (Toi) obj;
            return x == toi.x && y == toi.y;
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
}