import sys
n, m = map(int, input().split())
br = [int(sys.stdin.readline()) for i in range(m)]

dp = [0 for _ in range(n + 1)]

dp[0] = 1
if 1 not in br:
    dp[1] = 1
for i in range(2, n + 1):
    if i in br:
        continue
    else:
        dp[i] = dp[i - 1] + dp[i - 2]
        dp[i] = dp[i] % (10 ** 9 + 7)
print(dp[n])

