import java.util.*;

public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 1000000007;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;

	int max3(int a, int b, int c) {
		int max = ((a < b) ? b : a);
		return (max < c)? c : max;
	}
	
	void doIt() {
		int n = sc.nextInt() + 1;
		int m = sc.nextInt();
		boolean b[] = new boolean[n];
		Arrays.fill(b, true);
		for(int i = 0; i < m; i++) 
			b[sc.nextInt()] = false;
		int dp[] = new int[n];
		Arrays.fill(dp, 0);
		dp[0] = 1;
		for(int i = 0; i < n; i++) {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		}
		System.out.println(dp[n - 1]);
	}
	
	
	public static void main(String[] args) {
		new Main().doIt();
	}
} import java.util.*; util.* java public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 1000000007;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;

	int max3(int a, int b, int c) {
		int max = ((a < b) ? b : a);
		return (max < c)? c : max;
	}
	
	void doIt() {
		int n = sc.nextInt() + 1;
		int m = sc.nextInt();
		boolean b[] = new boolean[n];
		Arrays.fill(b, true);
		for(int i = 0; i < m; i++) 
			b[sc.nextInt()] = false;
		int dp[] = new int[n];
		Arrays.fill(dp, 0);
		dp[0] = 1;
		for(int i = 0; i < n; i++) {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		}
		System.out.println(dp[n - 1]);
	}
	
	
	public static void main(String[] args) {
		new Main().doIt();
	}
} Main Scanner sc = new Scanner(System.in); sc new Scanner(System.in) final int MOD = 1000000007; MOD 1000000007 final int MAX = Integer.MAX_VALUE; MAX Integer.MAX_VALUE Integer Integer.MAX_VALUE final long LMAX = Long.MAX_VALUE; LMAX Long.MAX_VALUE Long Long.MAX_VALUE int max3(int a, int b, int c) {
		int max = ((a < b) ? b : a);
		return (max < c)? c : max;
	} max3 {
		int max = ((a < b) ? b : a);
		return (max < c)? c : max;
	} int max = ((a < b) ? b : a); max ((a < b) ? b : a) (a < b) a b b a return (max < c)? c : max; (max < c)? c : max (max < c) max c c max int a a int b b int c c void doIt() {
		int n = sc.nextInt() + 1;
		int m = sc.nextInt();
		boolean b[] = new boolean[n];
		Arrays.fill(b, true);
		for(int i = 0; i < m; i++) 
			b[sc.nextInt()] = false;
		int dp[] = new int[n];
		Arrays.fill(dp, 0);
		dp[0] = 1;
		for(int i = 0; i < n; i++) {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		}
		System.out.println(dp[n - 1]);
	} doIt {
		int n = sc.nextInt() + 1;
		int m = sc.nextInt();
		boolean b[] = new boolean[n];
		Arrays.fill(b, true);
		for(int i = 0; i < m; i++) 
			b[sc.nextInt()] = false;
		int dp[] = new int[n];
		Arrays.fill(dp, 0);
		dp[0] = 1;
		for(int i = 0; i < n; i++) {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		}
		System.out.println(dp[n - 1]);
	} int n = sc.nextInt() + 1; n sc.nextInt() + 1 sc.nextInt() sc.nextInt sc 1 int m = sc.nextInt(); m sc.nextInt() sc.nextInt sc boolean b[] = new boolean[n]; b new boolean[n] n Arrays.fill(b, true) Arrays.fill Arrays b true for(int i = 0; i < m; i++) 
			b[sc.nextInt()] = false; int i = 0; int i = 0; i 0 i < m i m i++ i++ i b[sc.nextInt()] = false; b[sc.nextInt()] = false b[sc.nextInt()] b sc.nextInt() sc.nextInt sc false int dp[] = new int[n]; dp new int[n] n Arrays.fill(dp, 0) Arrays.fill Arrays dp 0 dp[0] = 1 dp[0] dp 0 1 for(int i = 0; i < n; i++) {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		} {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		} if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			} b[i] b i {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			} if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				} i + 1 < n i + 1 i 1 n {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				} dp[i + 1] = (dp[i + 1] + dp[i]) % MOD dp[i + 1] dp i + 1 i 1 (dp[i + 1] + dp[i]) % MOD (dp[i + 1] + dp[i]) dp[i + 1] dp i + 1 i 1 dp[i] dp i MOD if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				} i + 2 < n i + 2 i 2 n {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				} dp[i + 2] = (dp[i + 2] + dp[i]) % MOD dp[i + 2] dp i + 2 i 2 (dp[i + 2] + dp[i]) % MOD (dp[i + 2] + dp[i]) dp[i + 2] dp i + 2 i 2 dp[i] dp i MOD System.out.println(dp[n - 1]) System.out.println System.out System System.out dp[n - 1] dp n - 1 n 1 public static void main(String[] args) {
		new Main().doIt();
	} main {
		new Main().doIt();
	} new Main().doIt() new Main().doIt new Main() String[] args args public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 1000000007;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;

	int max3(int a, int b, int c) {
		int max = ((a < b) ? b : a);
		return (max < c)? c : max;
	}
	
	void doIt() {
		int n = sc.nextInt() + 1;
		int m = sc.nextInt();
		boolean b[] = new boolean[n];
		Arrays.fill(b, true);
		for(int i = 0; i < m; i++) 
			b[sc.nextInt()] = false;
		int dp[] = new int[n];
		Arrays.fill(dp, 0);
		dp[0] = 1;
		for(int i = 0; i < n; i++) {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		}
		System.out.println(dp[n - 1]);
	}
	
	
	public static void main(String[] args) {
		new Main().doIt();
	}
} public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 1000000007;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;

	int max3(int a, int b, int c) {
		int max = ((a < b) ? b : a);
		return (max < c)? c : max;
	}
	
	void doIt() {
		int n = sc.nextInt() + 1;
		int m = sc.nextInt();
		boolean b[] = new boolean[n];
		Arrays.fill(b, true);
		for(int i = 0; i < m; i++) 
			b[sc.nextInt()] = false;
		int dp[] = new int[n];
		Arrays.fill(dp, 0);
		dp[0] = 1;
		for(int i = 0; i < n; i++) {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		}
		System.out.println(dp[n - 1]);
	}
	
	
	public static void main(String[] args) {
		new Main().doIt();
	}
} Main
import java.util.*;

public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 1000000007;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;

	int max3(int a, int b, int c) {
		int max = ((a < b) ? b : a);
		return (max < c)? c : max;
	}
	
	void doIt() {
		int n = sc.nextInt() + 1;
		int m = sc.nextInt();
		boolean b[] = new boolean[n];
		Arrays.fill(b, true);
		for(int i = 0; i < m; i++) 
			b[sc.nextInt()] = false;
		int dp[] = new int[n];
		Arrays.fill(dp, 0);
		dp[0] = 1;
		for(int i = 0; i < n; i++) {
			if(b[i]) {
				if(i + 1 < n) {
					dp[i + 1] = (dp[i + 1] + dp[i]) % MOD;
				}
				if(i + 2 < n) {
					dp[i + 2] = (dp[i + 2] + dp[i]) % MOD;
				}
			}
		}
		System.out.println(dp[n - 1]);
	}
	
	
	public static void main(String[] args) {
		new Main().doIt();
	}
}
