import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;

public class Main {
    static class Reader
    {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    }
    public static void main(String args[]) throws IOException{
        Reader in = new Reader();
        int n = in.nextInt();
        int m = in.nextInt();
        long[] numOfWays = new long[n + 2];
        for (int i = 0; i < m; i++){
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        }
        numOfWays[0] = 0;
        numOfWays[1] = 1;
        for (int i = 2; i < numOfWays.length; i++){
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        }
        System.out.println(numOfWays[n + 1]);
    }
} import java.io.DataInputStream; DataInputStream java.io import java.io.FileInputStream; FileInputStream java.io import java.io.IOException; IOException java.io public class Main {
    static class Reader
    {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    }
    public static void main(String args[]) throws IOException{
        Reader in = new Reader();
        int n = in.nextInt();
        int m = in.nextInt();
        long[] numOfWays = new long[n + 2];
        for (int i = 0; i < m; i++){
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        }
        numOfWays[0] = 0;
        numOfWays[1] = 1;
        for (int i = 2; i < numOfWays.length; i++){
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        }
        System.out.println(numOfWays[n + 1]);
    }
} Main public static void main(String args[]) throws IOException{
        Reader in = new Reader();
        int n = in.nextInt();
        int m = in.nextInt();
        long[] numOfWays = new long[n + 2];
        for (int i = 0; i < m; i++){
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        }
        numOfWays[0] = 0;
        numOfWays[1] = 1;
        for (int i = 2; i < numOfWays.length; i++){
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        }
        System.out.println(numOfWays[n + 1]);
    } main {
        Reader in = new Reader();
        int n = in.nextInt();
        int m = in.nextInt();
        long[] numOfWays = new long[n + 2];
        for (int i = 0; i < m; i++){
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        }
        numOfWays[0] = 0;
        numOfWays[1] = 1;
        for (int i = 2; i < numOfWays.length; i++){
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        }
        System.out.println(numOfWays[n + 1]);
    } Reader in = new Reader(); in new Reader() int n = in.nextInt(); n in.nextInt() in.nextInt in int m = in.nextInt(); m in.nextInt() in.nextInt in long[] numOfWays = new long[n + 2]; numOfWays new long[n + 2] n + 2 n 2 for (int i = 0; i < m; i++){
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        } int i = 0; int i = 0; i 0 i < m i m i++ i++ i {
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        } {
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        } int ind = in.nextInt() + 1; ind in.nextInt() + 1 in.nextInt() in.nextInt in 1 numOfWays[ind] = -1 numOfWays[ind] numOfWays ind -1 1 if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            } numOfWays[ind] == numOfWays[ind - 1] numOfWays[ind] numOfWays ind numOfWays[ind - 1] numOfWays ind - 1 ind 1 {
                System.out.println(0);
                return;
            } System.out.println(0) System.out.println System.out System System.out 0 return; numOfWays[0] = 0 numOfWays[0] numOfWays 0 0 numOfWays[1] = 1 numOfWays[1] numOfWays 1 1 for (int i = 2; i < numOfWays.length; i++){
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        } int i = 2; int i = 2; i 2 i < numOfWays.length i numOfWays.length numOfWays numOfWays.length i++ i++ i {
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        } {
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        } if (numOfWays[i] == -1)
                continue; numOfWays[i] == -1 numOfWays[i] numOfWays i -1 1 continue; if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            } numOfWays[i - 1] == -1 numOfWays[i - 1] numOfWays i - 1 i 1 -1 1 {
                numOfWays[i] = numOfWays[i - 2];
                continue;
            } numOfWays[i] = numOfWays[i - 2] numOfWays[i] numOfWays i numOfWays[i - 2] numOfWays i - 2 i 2 continue; if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            } numOfWays[i - 2] == -1 numOfWays[i - 2] numOfWays i - 2 i 2 -1 1 {
                numOfWays[i] = numOfWays[i - 1];
                continue;
            } numOfWays[i] = numOfWays[i - 1] numOfWays[i] numOfWays i numOfWays[i - 1] numOfWays i - 1 i 1 continue; numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2] numOfWays[i] numOfWays i numOfWays[i - 1] + numOfWays[i - 2] numOfWays[i - 1] numOfWays i - 1 i 1 numOfWays[i - 2] numOfWays i - 2 i 2 numOfWays[i] %= 1000000007 numOfWays[i] numOfWays i 1000000007 System.out.println(numOfWays[n + 1]) System.out.println System.out System System.out numOfWays[n + 1] numOfWays n + 1 n 1 String args[] args static class Reader
    {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    } Reader final private int BUFFER_SIZE = 1 << 16; BUFFER_SIZE 1 << 16 1 16 private DataInputStream din; din private byte[] buffer; buffer private int bufferPointer bufferPointer bytesRead; bytesRead public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        } Reader {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        } din = new DataInputStream(System.in) din new DataInputStream(System.in) buffer = new byte[BUFFER_SIZE] buffer new byte[BUFFER_SIZE] BUFFER_SIZE bufferPointer = bytesRead = 0 bufferPointer bytesRead = 0 bytesRead 0 public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        } Reader {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        } din = new DataInputStream(new FileInputStream(file_name)) din new DataInputStream(new FileInputStream(file_name)) buffer = new byte[BUFFER_SIZE] buffer new byte[BUFFER_SIZE] BUFFER_SIZE bufferPointer = bytesRead = 0 bufferPointer bytesRead = 0 bytesRead 0 String file_name file_name public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        } readLine {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        } byte[] buf = new byte[64]; buf new byte[64] 64 int cnt = 0 cnt 0 c; c while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            } (c = read()) != -1 (c = read()) c read() read -1 1 {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            } if (c == '\n')
                    break; c == '\n' c '\n' break; buf[cnt++] = (byte) c buf[cnt++] buf cnt++ cnt (byte) c return new String(buf, 0, cnt); new String(buf, 0, cnt) public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        } nextInt {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        } int ret = 0; ret 0 byte c = read(); c read() read while (c <= ' ')
                c = read(); c <= ' ' c ' ' c = read() c read() read boolean neg = (c == '-'); neg (c == '-') c '-' if (neg)
                c = read(); neg c = read() c read() read do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9'); (c = read()) >= '0' && c <= '9' (c = read()) >= '0' (c = read()) c read() read '0' c <= '9' c '9' {
                ret = ret * 10 + c - '0';
            } ret = ret * 10 + c - '0' ret ret * 10 + c - '0' ret * 10 + c ret * 10 ret 10 c '0' if (neg)
                return -ret; neg return -ret; -ret ret return ret; ret public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        } nextLong {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        } long ret = 0; ret 0 byte c = read(); c read() read while (c <= ' ')
                c = read(); c <= ' ' c ' ' c = read() c read() read boolean neg = (c == '-'); neg (c == '-') c '-' if (neg)
                c = read(); neg c = read() c read() read do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9'); (c = read()) >= '0' && c <= '9' (c = read()) >= '0' (c = read()) c read() read '0' c <= '9' c '9' {
                ret = ret * 10 + c - '0';
            } ret = ret * 10 + c - '0' ret ret * 10 + c - '0' ret * 10 + c ret * 10 ret 10 c '0' if (neg)
                return -ret; neg return -ret; -ret ret return ret; ret public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        } nextDouble {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        } double ret = 0 ret 0 div = 1; div 1 byte c = read(); c read() read while (c <= ' ')
                c = read(); c <= ' ' c ' ' c = read() c read() read boolean neg = (c == '-'); neg (c == '-') c '-' if (neg)
                c = read(); neg c = read() c read() read do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9'); (c = read()) >= '0' && c <= '9' (c = read()) >= '0' (c = read()) c read() read '0' c <= '9' c '9' {
                ret = ret * 10 + c - '0';
            } ret = ret * 10 + c - '0' ret ret * 10 + c - '0' ret * 10 + c ret * 10 ret 10 c '0' if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            } c == '.' c '.' {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            } while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                } (c = read()) >= '0' && c <= '9' (c = read()) >= '0' (c = read()) c read() read '0' c <= '9' c '9' {
                    ret += (c - '0') / (div *= 10);
                } ret += (c - '0') / (div *= 10) ret (c - '0') / (div *= 10) (c - '0') c '0' (div *= 10) div 10 if (neg)
                return -ret; neg return -ret; -ret ret return ret; ret private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        } fillBuffer {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        } bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE) bytesRead din.read(buffer, bufferPointer = 0, BUFFER_SIZE) din.read din buffer bufferPointer = 0 bufferPointer 0 BUFFER_SIZE if (bytesRead == -1)
                buffer[0] = -1; bytesRead == -1 bytesRead -1 1 buffer[0] = -1 buffer[0] buffer 0 -1 1 private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        } read {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        } if (bufferPointer == bytesRead)
                fillBuffer(); bufferPointer == bytesRead bufferPointer bytesRead fillBuffer() fillBuffer return buffer[bufferPointer++]; buffer[bufferPointer++] buffer bufferPointer++ bufferPointer public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        } close {
            if (din == null)
                return;
            din.close();
        } if (din == null)
                return; din == null din null return; din.close() din.close din public class Main {
    static class Reader
    {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    }
    public static void main(String args[]) throws IOException{
        Reader in = new Reader();
        int n = in.nextInt();
        int m = in.nextInt();
        long[] numOfWays = new long[n + 2];
        for (int i = 0; i < m; i++){
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        }
        numOfWays[0] = 0;
        numOfWays[1] = 1;
        for (int i = 2; i < numOfWays.length; i++){
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        }
        System.out.println(numOfWays[n + 1]);
    }
} public class Main {
    static class Reader
    {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    }
    public static void main(String args[]) throws IOException{
        Reader in = new Reader();
        int n = in.nextInt();
        int m = in.nextInt();
        long[] numOfWays = new long[n + 2];
        for (int i = 0; i < m; i++){
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        }
        numOfWays[0] = 0;
        numOfWays[1] = 1;
        for (int i = 2; i < numOfWays.length; i++){
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        }
        System.out.println(numOfWays[n + 1]);
    }
} Main
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;

public class Main {
    static class Reader
    {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');

            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    }
    public static void main(String args[]) throws IOException{
        Reader in = new Reader();
        int n = in.nextInt();
        int m = in.nextInt();
        long[] numOfWays = new long[n + 2];
        for (int i = 0; i < m; i++){
            int ind = in.nextInt() + 1;
            numOfWays[ind] = -1;
            if (numOfWays[ind] == numOfWays[ind - 1]){
                System.out.println(0);
                return;
            }
        }
        numOfWays[0] = 0;
        numOfWays[1] = 1;
        for (int i = 2; i < numOfWays.length; i++){
            if (numOfWays[i] == -1)
                continue;
            if (numOfWays[i - 1] == -1){
                numOfWays[i] = numOfWays[i - 2];
                continue;
            }
            if (numOfWays[i - 2] == -1){
                numOfWays[i] = numOfWays[i - 1];
                continue;
            }
            numOfWays[i] = numOfWays[i - 1] + numOfWays[i - 2];
            numOfWays[i] %= 1000000007;
        }
        System.out.println(numOfWays[n + 1]);
    }
}
