题目描述
Given are a sequence of $N integers A_1, A_2, \ldots, A_N$ and a positive integer S.
For a pair of integers (L, R) such that $1\leq L \leq R \leq N$, let us define f(L, R) as follows:
- f(L, R) is the number of sequences of integers $(x_1, x_2, \ldots , x_k)$ such that $L \leq x_1 < x_2 < \cdots < x_k \leq R$ and $A_{x_1}+A_{x_2}+\cdots +A_{x_k} = S$.
Find the sum of f(L, R) over all pairs of integers (L, R) such that $1\leq L \leq R\leq N.$ Since this sum can be enormous, print it modulo 998244353.
Constraints
- All values in input are integers.
- $1 \leq N \leq 3000$
- $1 \leq S \leq 3000$
- $1 \leq A_i \leq 3000$
Input
Input is given from Standard Input in the following format:
N S
A_1 A_2 ... A_N
Output
Print the sum of f(L, R), modulo 998244353.
Examples
Input
3 4
2 2 4
Output
5
Input
5 8
9 9 9 9 9
Output
0
Input
10 10
3 1 4 1 5 9 2 6 5 3
Output
152
输入格式
见题面
输出格式
见题面
样例输入
10 10
3 1 4 1 5 9 2 6 5 3
样例输出
152