MOD = 998244353

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