input()
A = list(map(int,input().split()))
ans = 0
dic = {}
for a in A:
    ans += dic.get(a - 1, 0)
    ans %= 998244353
    dic[a] = (dic.get(a, 0) + dic.get(a - 1, 0) + 1) % 998244353
print(ans)