import sys
sys.setrecursionlimit(3000)

a=open(0)
N,_,*a = map(int, a.read().split())

dp = [-1 for _ in range(150000)]
dp[0] = 0
def rec(i):
    if dp[i] >= 0:
        return dp[i]
    if i in a:
        dp[i] = 0
        return 0
    if i<3:
        dp[i] = rec(i-1) + 1
        return dp[i]
    dp[i] = (rec(i-1)+rec(i-2))%1000000007
    return dp[i]
    
print(rec(N))


