import sys
input = sys.stdin.readline
n,m = map(int, input().split())
a = set(map(int, [input() for _ in range(m)]))
dp = [0] * (n+1)

#`dp[i] = i段目にいる通り数`
dp[0] = 1
dp[1] = 1
for i in range(2,n+1):
    if i in a:
        dp[i] = 0
    else: 
        dp[i] += (dp[i-1] + dp[i-2]) % (10 ** 9 + 7)

print(dp[-1])
