N,M = [int(i) for i in input().split()]
A = [int(input()) for _ in range(M)]

m = 10**9+7

memo = [1]*(N+3)
for i in range(3,N+3):
    memo[i] = memo[i-1] + memo[i-2]

memo[0] = 0

if M == 0:
    N -= 1
    
A.append(N+1)
p = A[0]
ans = memo[p]
for i in range(1,M+1):
    ans *= memo[A[i]-p-1]
    ans %= m
    p = A[i]

print(ans)
