import re
 
def convert_timecode(line):
    if "-->" in line:
        # Split the line into two parts using the arrow
        parts = line.strip().split(" --> ")
 
        # Process each part separately
        new_parts = []
        for i, part in enumerate(parts):
            if i == 0:
                # For the first timecode, insert a comma between the first two characters
                part = part[0] + "," + part[1:]
            else:
                # For the second timecode, remove the first character
                part = part[1:]
 
            # Remove the last digit from the milliseconds part
            hours, minutes, seconds_milliseconds = part.split(":")
            seconds, milliseconds = seconds_milliseconds.split(",")
            milliseconds = milliseconds[:-1]  # Remove the last digit
 
            # Replace the last colon before the milliseconds part with a dot
            new_part = f"{hours}:{minutes}:{seconds}.{milliseconds}"
            new_parts.append(new_part)
 
        # Join the parts back together using a comma
        new_line = ",".join(new_parts)
        return new_line + "\n"
    else:
        # If the line doesn't contain an arrow, return it unchanged
        return line
 
# Replace 'input.txt' with the name of your input file, and 'output.txt' with the name of your output file.
with open('input.txt', 'r', encoding='utf-8') as infile, open('output.txt', 'w', encoding='utf-8') as outfile:
    for line in infile:
        outfile.write(convert_timecode(line))