def Fib(n):
    a, b = 0, 1
    if n == 1:
        return a
    elif n == 2:
        return b
    else:
        for i in range(n-2):
            a, b = b, a + b
        return b

N, M = input().split()
breakFloor = []
for i in range(int(M)):
  breakFloor.append(int(input()))
outBreak = 0
jama = 0
for i in range(len(breakFloor)):
  jama += Fib(breakFloor[i])
  if i>=1 and breakFloor[i]-breakFloor[i-1]==1:
    outBreak = 1
all = Fib(int(N))

ans = (all - jama) % 1000000007
if outBreak ==1: ans = 0
print(ans)