n, m = list(map(int,input().split()))
t = list(map(int, input().split()))
lilist = [None for i in range(m)]
for i in range(m):
  li = [k for k in range(n)]
  for j in range(m):
    if j != i:
      li[t[j]-1], li[t[j]] = li[t[j]], li[t[j]-1]
  lilist[i] = tuple(li)
print(len(set(lilist)))