import java.util.*;
public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int M = sc.nextInt();
		Integer a[] = new Integer[M];
		long ans[] = new long[N + 1];
		Arrays.fill(ans, 0);
		for(int i = 0; i < M; i++) {
			a[i] = sc.nextInt();
			ans[a[i]] = -1;
		}
		ans[0] = (long)1;
		if(ans[1] != -1) {
			ans[1] = (long)1;
		} else {
			ans[1] = (long)0;
		}
		
		long p = 1000000007;
		for(int i = 2; i <= N; i++) {
			if(ans[i] != -1) {
				if(ans[i - 1] != -1) {
					ans[i] = ans[i - 1] % p;
				}
				if(ans[i - 2] != -1) {
					ans[i] = (ans[i] + ans[i - 2]) % p;
				}
			} else {
				ans[i] = (long)0;
			}
		}
		System.out.println(ans[N]);
	}
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz