The most binary substring

Everybody knows the number is saved with the binary string in the computer. Now, their have N (1 <= N <= 1000) binary strings I tell you, your task is tell me what is the most binary substring with K (1 <= K <= L) characters in the strings I give you. The length of each string is L (1 <= L <= 60). Output times of the most appearing binary substring.

Each line will contain three numbers N, L, K.
Following N lines, represent N binary strings.

One answer one line.

2 6 3
101011
110101
2 6 4
101011
110101

4
2 

In first case, the most sequence is 101, it appears 4 times.
In second case, the most sequence is 1010 or 0101, they all just appear 2 times.

威士忌

HDU 2007-11 Programming Contest