disregard a line from txt file to excel file in python

Question

I need to disregard lines when someone enters and leaves the channel as you can see in the below txt file.

7:52:01 AM sherr entered the channel
7:52:05 AM sherr
hello GOOD morning .
おはようございます。
7:52:09 AM sherr
Who ?
誰?
7:52:16 AM sherr
OK .
わかりました。
7:52:25 AM sherr left the channel.
7:52:32 AM gigi entered the channel
7:52:45 AM gigi
OK .
わかりました。

my code is supposed to output excel file that in every 3lines, they're in the same row and 1st line in 1st column, 2nd line in 2nd column and 3rd line in 3rd column. But I need to disregard the lines that has entered the channel and left the channel on it. what should I add? my codes looks like that as you can see below.

from openpyxl import Workbook
import copy

wb = Workbook()

with open('txtfile.txt', encoding='utf-8') as sherr:
    row = 1
    column = 1
    ws = wb.active
    for line in sherr:
        if column == 1:
            ## split the line and rejoin
            value = " ".join(line.strip().split(' ')[1:])
        else:
            value = line.strip()
            
        ws.cell(row=row, column=column, value=value)
        
        if (column := column + 1) > 3:
            row += 1
            column = 1
 
    for row in ws.iter_rows():
        for cell in row:      
            alignment = copy.copy(cell.alignment)
            alignment.wrapText=True
            cell.alignment = alignment
            
    for column_cells in ws.columns:
        length = max(len(str(cell.value)) for cell in column_cells)
        ws.column_dimensions[column_cells[0].column_letter].width = length

    wb.save('txt_to_exl.xlsx')