Chris is interested in analyzing the population density of the countries in the world. He has obtained a text file called pop.txt which contains lines of data records, each of which has the country name, the population, and the area $($in sq km$)$ of the country, separated by a comma.

Here are the first four lines of the file.

United$-$States, $28500000,9157520\mathrm{.}2$

Australia, $25500000,7682300\mathrm{.}0$

Indonesia, $273500000,1811570\mathrm{.}5$

Ghana, $31070000,227540\mathrm{.}0$

Assume that the country name contains no space and comma, and the maximum length is $63.$

Help Chris to write a complete Python program that reads and analyses the file and then prints the following results: $(1)$ the total population of all countries $(2)$ the country name with the largest area.

Remark: Use Python