import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
sys.setrecursionlimit(10**7)
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

n = ni()
l = n
r = -1
ans = 1
p = na()
q = [-1]*n
mod = 998244353
for i in range(n):
    q[p[i]] = i

for i in range(n):
    ans *= max([1,r-l-i][l<=q[i]<r],1)
    ans %= mod
    r = max(q[i]+1,r)
    l = min(q[i], l)
print(ans)