from collections import defaultdict
N = int(input())                    
P = list(map(int,input().split()))
dic = defaultdict(int)
for i in range(N):
    dic[P[i]] = i
l = 0
r = 0
ans = 1
mod = 998244353
for x in range(N):
    if x == 0:
        l = dic[x]
        r = dic[x]
    else:
        index = dic[x]
        if l < index < r:
            ans *= (r-l+1-x)
            ans %= mod
        else:
            l = min(index,l)
            r = max(index,r)
print(ans)