n, m = map(int, input().split())
breaks = []
for _ in range(m):
  breaks.append(int(input())-1)
stairs = [0 for _ in range(n)]

if 0 not in breaks:
  stairs[0]=1

if 1 not in breaks:
  stairs[1]=1  

for i in range(n):
  if i+1 not in breaks:
    if i+1>=n:
      pass
    else:
      stairs[i+1]=stairs[i]+stairs[i+1]
  if i+2 not in breaks:
    if i+2>=n:
      pass
    else:
      stairs[i+2]=stairs[i]+stairs[i+2]
      
print(stairs[-1]%1000000007)
  