def main():
	n, s, *a = map(int, open(0).read().split())
	ans = 0
	mod = 998244353
	dp = [0] * (s + 1)
	for i, x in enumerate(a):
		dp[0] += 1
		if x > s:continue
		ans += dp[s - x] * (n - i)
		ans %= mod
		dp = dp[:x] + [(dp[j] + dp[j - x]) % mod for j in range(x, s + 1)]
	print(ans)
	
if __name__=="__main__":
	main()

