Load only particular field in PIG?

This is my file:

Col1, Col2, Col3, Col4, Col5

I need only Col2 and Col3.

Currently I'm doing this:

a = load 'input' as (Col1:chararray, 
                     Col2:chararray, 
                     Col3:chararray, 
                     Col4:chararray);
b = foreach a generate Col2, Col3;

Is there a way to do directly load only Col2 and Col3 instead of loading the whole input and then generate required columns?