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

public class Main {

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

  static int INF = 1 << 30;
  static long LINF = 1L << 55;
  static int MOD = 1000000007;
  static int[] mh4 = {0, -1, 1, 0};
  static int[] mw4 = {-1, 0, 0, 1};
  static int[] mh8 = {-1, -1, -1, 0, 0, 1, 1, 1};
  static int[] mw8 = {-1, 0, 1, -1, 1, -1, 0, 1};

  static class TaskX {

    public void solve(int testNumber, MyInput in, PrintWriter out) {

      int n = in.nextInt(), m = in.nextInt();
      long[] f = new long[100010];
      boolean[] d = new boolean[100010];
      for (int i = 0; i < m; i++) {
        int a = in.nextInt();
        d[a] = true;
      }

      f[0] = 1;

      for (int i = 0; i < 100005; i++) {
        if (!d[i+1]) {
          f[i+1] += f[i];
          f[i+1] %= MOD;
        }

        if (!d[i+2]) {
          f[i+2] += f[i];
          f[i+2] %= MOD;
        }
      }

      out.println(f[n]);
    }
  }

  static class MyInput {
    private final BufferedReader in;
    private static int pos;
    private static int readLen;
    private static final char[] buffer = new char[1024 * 8];
    private static char[] str = new char[500 * 8 * 2];
    private static boolean[] isDigit = new boolean[256];
    private static boolean[] isSpace = new boolean[256];
    private static boolean[] isLineSep = new boolean[256];

    static {
      for (int i = 0; i < 10; i++) {
        isDigit['0' + i] = true;
      }
      isDigit['-'] = true;
      isSpace[' '] = isSpace['\r'] = isSpace['\n'] = isSpace['\t'] = true;
      isLineSep['\r'] = isLineSep['\n'] = true;
    }

    public MyInput(InputStream is) {
      in = new BufferedReader(new InputStreamReader(is));
    }

    public int read() {
      if (pos >= readLen) {
        pos = 0;
        try {
          readLen = in.read(buffer);
        } catch (IOException e) {
          throw new RuntimeException();
        }
        if (readLen <= 0) {
          throw new MyInput.EndOfFileRuntimeException();
        }
      }
      return buffer[pos++];
    }

    public int nextInt() {
      int len = 0;
      str[len++] = nextChar();
      len = reads(len, isSpace);
      int i = 0;
      int ret = 0;
      if (str[0] == '-') {
        i = 1;
      }
      for (; i < len; i++)
        ret = ret * 10 + str[i] - '0';
      if (str[0] == '-') {
        ret = -ret;
      }
      return ret;
    }

    public long nextLong() {
      int len = 0;
      str[len++] = nextChar();
      len = reads(len, isSpace);
      int i = 0;
      long ret = 0;
      if (str[0] == '-') {
        i = 1;
      }
      for (; i < len; i++)
        ret = ret * 10 + str[i] - '0';
      if (str[0] == '-') {
        ret = -ret;
      }
      return ret;
    }

    public char nextChar() {
      while (true) {
        final int c = read();
        if (!isSpace[c]) {
          return (char) c;
        }
      }
    }

    public String nextString() {
      return new String(nextChars());
    }

    public char[] nextChars() {
      int len = 0;
      str[len++] = nextChar();
      len = reads(len, isSpace);
      return Arrays.copyOf(str, len);
    }

    public char[][] next2DChars(int h, int w) {
      char[][] s = new char[h][w];
      for (int i = 0; i < h; i++) {
        s[i] = nextChars();
      }
      return s;
    }

    int reads(int len, boolean[] accept) {
      try {
        while (true) {
          final int c = read();
          if (accept[c]) {
            break;
          }
          if (str.length == len) {
            char[] rep = new char[str.length * 3 / 2];
            System.arraycopy(str, 0, rep, 0, str.length);
            str = rep;
          }
          str[len++] = (char) c;
        }
      } catch (MyInput.EndOfFileRuntimeException e) {
      }
      return len;
    }

    public int[] nextIntArray(final int n) {
      final int[] res = new int[n];
      for (int i = 0; i < n; i++) {
        res[i] = nextInt();
      }
      return res;
    }

    public int[] nextIntArray1Index(final int n) {
      final int[] res = new int[n + 1];
      for (int i = 1; i < n + 1; i++) {
        res[i] = nextInt();
      }
      return res;
    }

    public int[] nextIntArrayDec(final int n) {
      final int[] res = new int[n];
      for (int i = 0; i < n; i++) {
        res[i] = nextInt() - 1;
      }
      return res;
    }

    public long[] nextLongArray(final int n) {
      final long[] res = new long[n];
      for (int i = 0; i < n; i++) {
        res[i] = nextLong();
      }
      return res;
    }

    public long[] nextLongArray1Index(final int n) {
      final long[] res = new long[n + 1];
      for (int i = 1; i < n + 1; i++) {
        res[i] = nextLong();
      }
      return res;
    }

    public long[] nextLongArrayDec(final int n) {
      final long[] res = new long[n];
      for (int i = 0; i < n; i++) {
        res[i] = nextLong() - 1;
      }
      return res;
    }

    public double nextDouble() {
      return Double.parseDouble(nextString());
    }

    public double[] nextDoubleArray(int n) {
      double[] res = new double[n];
      for (int i = 0; i < n; i++) {
        res[i] = nextDouble();
      }
      return res;
    }

    static class EndOfFileRuntimeException extends RuntimeException {
    }

  }

}


Measured memory_bytes: 24148