import math
import string
import collections
from collections import Counter
from collections import deque
import sys
sys.setrecursionlimit(2*10**5)


def readints():
    return list(map(int, input().split()))


def nCr(n, r):
    return math.factorial(n)//(math.factorial(n-r)*math.factorial(r))


def has_duplicates2(seq):
    seen = []
    for item in seq:
        if not(item in seen):
            seen.append(item)
    return len(seq) != len(seen)


def divisor(n):
    divisor = []
    for i in range(1, n+1):
        if n % i == 0:
            divisor.append(i)
    return divisor


# coordinates
dx = [-1, -1, -1, 0, 0, 1, 1, 1]
dy = [-1, 0, 1, -1, 1, -1, 0, 1]

N, M = map(int, input().split())
a = []
for _ in range(M):
    a.append(int(input()))

safe = [True]*(N+1)
for i in range(M):
    safe[(a[i])] = False


def func(i):
    global safe

    if not(safe[i]):
        return 0
    if i == 0:
        return 1
    if i == 1:
        return 1
    if i >= 2:
        return func(i-1)+func(i-2)


print(func(N) % 1000000007)

# print(a)
# dp = [0]*(N+1)
# print('safe', safe)
# dp[0] = 1
# if safe[1]:
#    dp[1] = 1
# for i in range(2, N+1):
#    if safe[i]:
#        dp[i] = dp[i-1]+dp[i-2]
#    if not(safe[i]):
#        dp[i] = 0
# print('dp', dp)
# print(dp[N] % 1000000007)
