I want to change THERMISTOR PIN 0 to PIN 1 in RAMBo 1.3 Firmware

Hello!

First of all, sorry for my english.

I'm triying to change by code, the Thermistor OUT0 to Thermistor OUT1 but i' don't know where I should do the modification, I've downloaded the firmware MARLIN.ino and i'm looking for the pins assignment but i can't find it