import sys
sys.setrecursionlimit(50000)

n, m = map(int, input().split())
bad = [int(input()) for _ in range(m)]
MOD = int(1e9+7)

memo = {0:1, 1:1}
for i in bad:
    memo[i] = 0

def fib(n, mod):
    if n not in memo:
        memo[n] = (fib(n-1, mod) + fib(n-2, mod)) % mod
    return memo[n]

print(fib(n, MOD))