如何使用pdftotext将包含表格的pdf文件转换为csv

I have a pdf file here. It contains a table. I need to convert it to csv using pdftable.

I've tried to format it with the code below but i keep getting a bad format. here.

pdftotext -layout firstthree.pdf - \
 | sed '$d'                                                  \
 | sed -r 's/ +/,/g;'                                 \
 > output.csv

I need it to appear like this