a = list(map(int, input().split()))
#print(a)
b=[0]*a[1]
c=[0]*(a[1]+1)
b[0]=int(input())
c[0]=b[0]-0
for x in range(a[1]-1):
    b[x+1]=int(input())
    c[x+1]=b[x+1]-b[x]-1
c[-1]=a[0]-b[-1]
max = 0
min = a[0]+100
for x in c:
    if x>max:
        max=x
    if x<min:
        min=x
        
#print(c)
#print(max," ",min)
if min==0:
    print(0)
else:
    num=[0]*(max)
    for x in range(max):
        if x==0:
            num[0]=1
        elif x==1:
            num[1]=1
        else:
            num[x]=num[x-1]+num[x-2]
        #print("num[",x,"]=",num[x])
        
    answer=1
    try:
        for x in c:
            answer *=num[x-1]
            if answer==0:
                print(0)
                break
            else:
                answer%=1000000007
        print(answer)
    except:
        print(0)