A radio station logs its programming as a single continuous string of lowercase letters, one letter per minute-slot, where each letter is a code identifying which program aired during that minute. The station calls a contiguous block of exactly k minute-slots a clean block if no program code repeats anywhere inside that block -- every one of the k letters in the block is different from every other letter in it.

Given the full log and the block length k, count how many clean blocks occur in the log (a block starting at each possible position counts separately, so overlapping blocks are all counted).

Input format

s
k

s is the programming log and k is the block length.

Output format

Print a single integer: the number of contiguous substrings of s of length exactly k in which all k characters are pairwise distinct.

Constraints

• 1 <= k <= |s| <= 100000
• s consists only of lowercase English letters a to z

abcab
3

3

aaaa
2

0