n,m = map(int, input().split())
a_list = []
for i in range(m):
    a_list.append(int(input()))

# memo = [-1 for _ in range(n)]
step_now = 0
step_1   = 0
step_2   = 0
DIV_NUM = 1000000007
if 1 in a_list:
    step_now = 0
else:
    step_now = 1
for i in range(1, n):
    if i == 1:
        step_1 = step_now
        if i+1 in a_list:
            step_now = 0
        else:
#             memo[i] = (memo[0] + 1) % DIV_NUM
            step_now = step_1 + 1
    else:
        step_2 = step_1
        step_1 = step_now % DIV_NUM
        if i+1 in a_list:
            step_now = 0
        else:
#             memo[i] = (memo[i-1] + memo[i-2]) % DIV_NUM
            step_now = (step_1 + step_2) % DIV_NUM
    if step_now ==  step_1 == step_2 == 0:
        break

print(step_now)