class Solution {

public int takeCharacters(String s, int k) {

int[] counter = new int[3];

int n = s.length();

for (char c : s.toCharArray()) {

counter[c - 'a']++;

}

for (int i = 0; i < 3; i++) {

if (counter[i] < k) {

return -1;

}

}

int[] window = new int[3];

int left = 0;

int maxWindow = 0;

for (int right = 0; right < n; right++) {

window[s.charAt(right) - 'a']++;

while (left <= right &&

(counter[0] - window[0] < k || counter[1] - window[1] < k || counter[2] - window[2] < k)) {

window[s.charAt(left) - 'a']--;

left++;

}

maxWindow = Math.max(maxWindow, right - left + 1);

}

return n - maxWindow;

}

}