import sys
input = sys.stdin.readline
N = int(input())
a = list(map(int, input().split()))
mod = 998244353
reva = [0] * N
for i in range(N): reva[a[i]] = i

l = reva[: ]
r = reva[: ]
for i in range(N - 1):
  l[i + 1] = min(l[i], reva[i + 1])
  r[i + 1] = max(r[i], reva[i + 1])
  
#print(l, r, reva)

class Factorial:
  def __init__(self, n, mod):
    self.mod = mod
    self.f = [1]
    for i in range(1, n + 1): self.f.append(self.f[-1] * i % mod)
    self.i = [pow(self.f[-1], mod - 2, mod)]
    for i in range(1, n + 1)[: : -1]: self.i.append(self.i[-1] * i % mod)
    self.i.reverse()
  def factorial(self, i): return self.f[i]
  def ifactorial(self, i): return self.i[i]
  def combi(self, n, k): return self.f[n] * self.i[n - k] % self.mod * self.i[k] % self.mod
  def permi(self, n, k): return self.f[n] * self.i[n - k] % self.mod

f = Factorial(N, mod)
res = 1
dsm = 0
ll = l[0]
rr = r[0]
for i in range(1, N):
  d = max(0, ll - l[i] - 1) + max(0, r[i] - rr - 1)
  if d == 0 and ll == l[i] and rr == r[i]:
    res *= dsm
    res %= mod
    dsm -= 1
  else: dsm += d
  ll = l[i]
  rr = r[i]
  #print(res, d, ll, rr, dsm)
if dsm > 0:
  res *= f.factorial(dsm)
  res %= mod
print(res)