FileInputStream inputStream = new FileInputStream(new BufferedReader(new InputStreamReader(System.in)).readLine()); long[] arr = new long[256]; while (inputStream.available() > 0) arr[inputStream.read()]++; ВОТ В ЭТОЙ ЧАСТИ inputStream.close(); for (int i = 0; i < 256 ; i++) { И ПО ЦИКЛУ if (arr[i] > 2) System.out.print(i+" "); }