#P1477F. Nezzar and Chocolate Bars

    ID: 5764 Type: RemoteJudge 5000ms 512MiB Tried: 0 Accepted: 0 Difficulty: (None) Uploaded By: Tags>combinatoricsfftmathprobabilities*3500

Nezzar and Chocolate Bars

No submission language available for this problem.

Description

Nezzar buys his favorite snack — nn chocolate bars with lengths l1,l2,,lnl_1,l_2,\ldots,l_n. However, chocolate bars might be too long to store them properly!

In order to solve this problem, Nezzar designs an interesting process to divide them into small pieces. Firstly, Nezzar puts all his chocolate bars into a black box. Then, he will perform the following operation repeatedly until the maximum length over all chocolate bars does not exceed kk.

  • Nezzar picks a chocolate bar from the box with probability proportional to its length xx.
  • After step 11, Nezzar uniformly picks a real number r(0,x)r \in (0,x) and divides the chosen chocolate bar into two chocolate bars with lengths rr and xrx-r.
  • Lastly, he puts those two new chocolate bars into the black box.

Nezzar now wonders, what is the expected number of operations he will perform to divide his chocolate bars into small pieces.

It can be shown that the answer can be represented as PQ\frac{P}{Q}, where PP and QQ are coprime integers and Q≢0Q \not \equiv 0 (mod998244353\bmod 998\,244\,353). Print the value of PQ1mod  998244353P\cdot Q^{-1} \mod 998\,244\,353.

The first line contains two integers nn and kk (1n50,1k20001 \le n \le 50, 1 \le k \le 2000).

The second line contains nn integers l1,l2,,lnl_1, l_2, \ldots, l_n (1li1 \le l_i, i=1nli2000\sum_{i=1}^{n} l_i \le 2000).

Print a single integer — the expected number of operations Nezzar will perform to divide his chocolate bars into small pieces modulo 998244353998\,244\,353.

Input

The first line contains two integers nn and kk (1n50,1k20001 \le n \le 50, 1 \le k \le 2000).

The second line contains nn integers l1,l2,,lnl_1, l_2, \ldots, l_n (1li1 \le l_i, i=1nli2000\sum_{i=1}^{n} l_i \le 2000).

Output

Print a single integer — the expected number of operations Nezzar will perform to divide his chocolate bars into small pieces modulo 998244353998\,244\,353.

Samples

Sample Input 1

1 1
2

Sample Output 1

4

Sample Input 2

1 1
1

Sample Output 2

0

Sample Input 3

1 5
1234

Sample Output 3

15630811

Sample Input 4

2 1
2 3

Sample Output 4

476014684

Sample Input 5

10 33
10 20 30 40 50 60 70 80 90 100

Sample Output 5

675105648