#! /usr/bin/env python
import sys

help_text = "Syntax: tracking_splitter [tracking_num[, tracking_num, ...]]\n"

tracking_nums = []
if len(sys.argv) < 2:
    print("Capturing from stdin. Enter tracking numbers separated by newlines.\n"+
            "Enter 'exit' to finish")
    tracking_num = ""
    while True:
        tracking_num = input().strip()
        if tracking_num == "":
            continue
        if 'exit' in tracking_num.lower():
            print()
            break
        tracking_nums.append(tracking_num)
else:
    if sys.argv[1] in ['-h', '--help']:
        print(help_text)
        sys.exit()
    tracking_nums = sys.argv[1:]

BOLD_START = "\033[1m"
BOLD_END = "\033[0m"

result = []
bold_on = False
for tracking_num in tracking_nums:
    for idx, c in enumerate(tracking_num):
        is_mod_4 = idx % 4 == 0
        if is_mod_4 and idx != 0:
            if not bold_on:
                result.append(BOLD_START)
                bold_on = True
            else:
                result.append(BOLD_END)
                bold_on = False
            result.append(' ')
        result.append(c)

    if bold_on:
        result.append(BOLD_END)
        bold_on = False
    if tracking_num != tracking_nums[-1]:
        result.append('\n')

print("".join(result))