import sys
sys.setrecursionlimit(10**7)
def lmi(): return list(map(int, input().split()))

n, m = lmi()

l = [0] * (n+1)
l[0] = 1

a = int(input())
k = 1
for i in range(n+1):

    if i != a:
        if i == 1:
            l[i] = 1
        elif i >= 2:
            l[i] = l[i-1] + l[i-2]
            l[i] %= 1000000007
    else:
        k += 1
        if k <= m:
            a = int(input())



#print(l)
print(l[n] % 1000000007)
