Не записывает вторую половину

package com.javarush.task.task18.task1808; import java.io.*; /* Разделение файла */ public class Solution { public static void main(String[] args) throws Exception { BufferedReader fileNames = new BufferedReader(new InputStreamReader(System.in)); String file1 = fileNames.readLine(); String file2 = fileNames.readLine(); String file3 = fileNames.readLine(); try(FileInputStream fileInputStream = new FileInputStream(file1); FileOutputStream fileOutputStream1 = new FileOutputStream(file2); FileOutputStream fileOutputStream2 = new FileOutputStream(file3)){ byte[] buffer = new byte[fileInputStream.available()]; int countBytes = fileInputStream.read(buffer); if (countBytes % 2 == 0) { fileOutputStream1.write(buffer, 0, countBytes / 2); fileOutputStream2.write(buffer, countBytes / 2 + 1, countBytes); } else { fileOutputStream1.write(buffer, 0, (countBytes + 1) / 2); fileOutputStream2.write(buffer, (countBytes - 1) / 2, countBytes); } } catch (Exception e){ e.printStackTrace(); } } }