Longest Substring with At Most K Distinct Characters

You are given a string S and an integer K. Your task is to find the length of the longest substring of S that contains at most K distinct characters.

More formally, if a substring starts at index i and ends at index j, then its length is given by \( j - i + 1 \). The substring is valid if it contains at most K distinct characters.

If no valid substring exists, print 0.

inputFormat

The input consists of two lines:

• The first line contains the string S.
• The second line contains the integer K.

outputFormat

Output a single integer representing the length of the longest substring of S that contains at most K distinct characters.

eceba
2

3