#129c
N,M = map(int, input().split())

now_step = 0
ans = 1
calculated_jump = {}
mod_number = 1000000007 

#開いている段数の移動パターンを算出する関数
def jump(now_step):
    
    if now_step in calculated_jump:
        return calculated_jump[now_step]
    else:
        if now_step == 2:
            return 2
        elif now_step == 1:
            return 1
        else:
            if now_step not in calculated_jump:
                calculated_jump[now_step] = jump(now_step-1) + jump(now_step-2)
                return jump(now_step-1) + jump(now_step-2)

for _ in range(M):
    a = int(input())
    
    if a == now_step:
        print("0")
        break
    elif a - 1 - now_step != 0: #左記成立時は1通りしかない。
        target_step_count = a - 1 - now_step #aは踏んではいけない段なので、その前がターゲット
        ans = ans * jump(target_step_count)
            
    now_step = a + 1

else:
    if now_step != N:
        target_step_count = N - now_step
        ans = ans * jump(target_step_count)
    
    print(ans % mod_number)