import sys
n,m = map(int,input().split())
a = []
for i in range(m):
    a.append(int(input()))
fib = [1,1]
for i in range(n):
    fib.append((fib[i]+fib[i+1])%1000000007)
if m == 0:
	print(fib[n])
    sys.exit()
answer = fib[a[0]-1]
for i in range(m-1):
    if a[i] + 1 == a[i+1]:
        answer = 0
    else:
        answer = answer * fib[a[i+1]-a[i]-2] % 1000000007
answer = answer * fib[n-a[m-1]-1] % 1000000007
print(answer)
