write a go solution for Description:
A subarray of array a from index l to the index r is the array [a_l,a_l+1,...,a_r]. The number of occurrences of the array b in the array a is the number of subarrays of a such that they are equal to b.

You are given n arrays A_1,A_2,...,A_n; the elements of these arrays are integers from 1 to k. You have to build an array a consisting of m integers from 1 to k in such a way that, for every given subarray A_i, the number of occurrences of A_i in the array a is not less than the number of occurrences of each non-empty subarray of A_i in a. Note that if A_i doesn't occur in a, and no subarray of A_i occurs in a, this condition is still met for A_i.

Your task is to calculate the number of different arrays a you can build, and print it modulo 998244353.

Input Format:
The first line contains three integers n, m and k (1<=n,m,k<=3*10^5) — the number of the given arrays, the desired length of the array a, and the upper bound on the values in the arrays.

Then n lines follow. The i-th line represents the array A_i. The first integer in the i-th line is c_i (1<=c_i<=m) — the number of elements in A_i; then, c_i integers from 1 to k follow — the elements of the array A_i.

Additional constraint on the input: sumlimits_i=1^nc_i<=3*10^5; i. e., the number of elements in the given arrays in total does not exceed 3*10^5.

Output Format:
Print one integer — the number of different arrays a you can build, taken modulo 998244353.

Note:
None. Output only the code with no comments, explanation, or additional text.