import java.util.*;

public class Main {

    public static void main(String[] args) {
//        long startTime = System.currentTimeMillis();
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        long[] nValue = new long[N + 1];
        nValue[0] = 1L;
        for (int i = 0; i < M; i++) {
            int a = scanner.nextInt();
            nValue[a] = -1;
        }
        scanner.close();

        long calcValue = 1000000007;

        for (int i = 0; i < N + 1; i++) {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        }

        System.out.println(nValue[N]);
    }
} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
//        long startTime = System.currentTimeMillis();
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        long[] nValue = new long[N + 1];
        nValue[0] = 1L;
        for (int i = 0; i < M; i++) {
            int a = scanner.nextInt();
            nValue[a] = -1;
        }
        scanner.close();

        long calcValue = 1000000007;

        for (int i = 0; i < N + 1; i++) {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        }

        System.out.println(nValue[N]);
    }
} Main public static void main(String[] args) {
//        long startTime = System.currentTimeMillis();
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        long[] nValue = new long[N + 1];
        nValue[0] = 1L;
        for (int i = 0; i < M; i++) {
            int a = scanner.nextInt();
            nValue[a] = -1;
        }
        scanner.close();

        long calcValue = 1000000007;

        for (int i = 0; i < N + 1; i++) {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        }

        System.out.println(nValue[N]);
    } main {
//        long startTime = System.currentTimeMillis();
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        long[] nValue = new long[N + 1];
        nValue[0] = 1L;
        for (int i = 0; i < M; i++) {
            int a = scanner.nextInt();
            nValue[a] = -1;
        }
        scanner.close();

        long calcValue = 1000000007;

        for (int i = 0; i < N + 1; i++) {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        }

        System.out.println(nValue[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[] nValue = new long[N + 1]; nValue new long[N + 1] N + 1 N 1 nValue[0] = 1L nValue[0] nValue 0 1L for (int i = 0; i < M; i++) {
            int a = scanner.nextInt();
            nValue[a] = -1;
        } int i = 0; int i = 0; i 0 i < M i M i++ i++ i {
            int a = scanner.nextInt();
            nValue[a] = -1;
        } {
            int a = scanner.nextInt();
            nValue[a] = -1;
        } int a = scanner.nextInt(); a scanner.nextInt() scanner.nextInt scanner nValue[a] = -1 nValue[a] nValue a -1 1 scanner.close() scanner.close scanner long calcValue = 1000000007; calcValue 1000000007 for (int i = 0; i < N + 1; i++) {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        } int i = 0; int i = 0; i 0 i < N + 1 i N + 1 N 1 i++ i++ i {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        } {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        } if (nValue[i] < 0) {
                continue;
            } nValue[i] < 0 nValue[i] nValue i 0 {
                continue;
            } continue; int one = i + 1; one i + 1 i 1 if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            } one <= N && nValue[one] >= 0 one <= N one N nValue[one] >= 0 nValue[one] nValue one 0 {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            } nValue[one] = (nValue[i] + nValue[one]) % calcValue nValue[one] nValue one (nValue[i] + nValue[one]) % calcValue (nValue[i] + nValue[one]) nValue[i] nValue i nValue[one] nValue one calcValue int two = i + 2; two i + 2 i 2 if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            } two <= N && nValue[two] >= 0 two <= N two N nValue[two] >= 0 nValue[two] nValue two 0 {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            } nValue[two] = (nValue[i] + nValue[two]) % calcValue nValue[two] nValue two (nValue[i] + nValue[two]) % calcValue (nValue[i] + nValue[two]) nValue[i] nValue i nValue[two] nValue two calcValue System.out.println(nValue[N]) System.out.println System.out System System.out nValue[N] nValue N String[] args args public class Main {

    public static void main(String[] args) {
//        long startTime = System.currentTimeMillis();
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        long[] nValue = new long[N + 1];
        nValue[0] = 1L;
        for (int i = 0; i < M; i++) {
            int a = scanner.nextInt();
            nValue[a] = -1;
        }
        scanner.close();

        long calcValue = 1000000007;

        for (int i = 0; i < N + 1; i++) {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        }

        System.out.println(nValue[N]);
    }
} public class Main {

    public static void main(String[] args) {
//        long startTime = System.currentTimeMillis();
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        long[] nValue = new long[N + 1];
        nValue[0] = 1L;
        for (int i = 0; i < M; i++) {
            int a = scanner.nextInt();
            nValue[a] = -1;
        }
        scanner.close();

        long calcValue = 1000000007;

        for (int i = 0; i < N + 1; i++) {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        }

        System.out.println(nValue[N]);
    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
//        long startTime = System.currentTimeMillis();
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int M = scanner.nextInt();
        long[] nValue = new long[N + 1];
        nValue[0] = 1L;
        for (int i = 0; i < M; i++) {
            int a = scanner.nextInt();
            nValue[a] = -1;
        }
        scanner.close();

        long calcValue = 1000000007;

        for (int i = 0; i < N + 1; i++) {
            if (nValue[i] < 0) {
                continue;
            }
            // 1段上がる場合
            int one = i + 1;
            if (one <= N && nValue[one] >= 0) {
                nValue[one] = (nValue[i] + nValue[one]) % calcValue;
            }
            // 2段上がる場合
            int two = i + 2;
            if (two <= N && nValue[two] >= 0) {
                nValue[two] = (nValue[i] + nValue[two]) % calcValue;
            }
        }

        System.out.println(nValue[N]);
    }
}
