Arduino for STM32

Hello.
I am trying to set D0 and D1 pins on the Nucleo-F103RB board as analog input. These two pins are PA3 and PA2 and are the third and second inputs of ADC (in STM32F103RB). I have written this program and connected the output pin of a potentiometer to PA2. I change the voltage on PA2 between 0 ...