import numpy as np

n,s=map(int,input().split())
a=list(map(int,input().split()))

dp=[np.zeros(s+1,dtype=np.int64) for _ in range(n+1)]
for i in range(n+1):
    dp[i][0]=1
ans=0

for i,w in enumerate(a):
    dp[i]+=dp[i-1]
    dp[i][w:]+=dp[i-1][:-w]
    ans+=dp[i][-1]
    ans%=998244353

print(ans)