COCI '11 Contest 6 #6 Košare
View as PDFMirko found  boxes with various forgotten toys in his attic. There are 
 different toys, numbered 
 through 
, but each of those can appear multiple times across various boxes.
Mirko decided that he will choose some boxes in a way that there is at least one toy of each kind present, and throw the rest of the boxes away.
Determine the number of ways in which Mirko can do this.
Input Specification
The first line of input contains two integers  and 
 
. Each of the following 
 lines contains an integer 
 
 followed by 
 distinct integers from the interval 
, representing the toys in that box.
Output Specification
The first and only line of output should contain the requested number of ways modulo .
Scoring
In test cases worth 50% of total points,  and 
 will hold.
In test cases worth 70% of total points,  and 
 will hold.
Sample Input 1
3 3
3 1 2 3
3 1 2 3
3 1 2 3
Sample Output 1
7
Sample Input 2
3 3
1 1
1 2
1 3
Sample Output 2
1
Sample Input 3
4 5
2 2 3
2 1 2
4 1 2 3 5
4 1 2 4 5
Sample Output 3
6
Comments
Exactly the same as https://codeforces.com/problemset/problem/449/D