n, m = map(int, input().split())
now_step = 0
# count=1*a+2*bとなるような、0以上の全てのa,bについて、1をa個、2をb個並べる並べ方を返す.
# [1,(a+b)]からa個を選ぶ選び方と同じ
# ただし、これはnumber-1とnumber-2が分かっている場合は、number-1から1つ、あるいはnumber-2から二つ進む進み方の和で表せる
# よって、counte_steps(number) = count_steps(number-1) + count_steps(number-2)
# 初期値はcount_steps(1) = 1, count_steps(2) = 2,count_steps(0) = 0
checked_steps = {-1:0, 0:1, 1:1, 2:2}
divide_num = 1000000007 

for i in range(3, n):
    checked_steps[i] = (checked_steps[i-1] + checked_steps[i-2]) % divide_num

all_count = 1
for i in range(m):
    a = int(input())
    all_count = (all_count * checked_steps[a - 1 - now_step]) % divide_num
    now_step = a + 1
all_count = (all_count * checked_steps[n - now_step]) % divide_num
print(all_count % divide_num)