import sys
sys.setrecursionlimit(10**6)

n, m = map(int, input().split())
a = [int(input()) for _ in range(m)]
a.append(n+1)
seq = [a[0]]

for i in range(m):
    d = a[i+1] - a[i] - 1
    if d == 0:
        print(0)
        sys.exit()
    seq.append(d)

memo = [-1] * 10**5
def fib(i):
    if i == 0: return 0
    elif i == 1: return 1
    elif memo[i] != -1: return memo[i]
    else:
        memo[i] = fib(i-1) + fib(i-2)
        return memo[i]

ans = 1
for s in seq:
    ans *= fib(s)
print(ans % 1000000007)
