Help with pulse_counter config

[MnM]

Hi,

I would like some help to configure an input for count my water with pulse_counter

I need to use a port that is connected directly to the ESP module.

What PIN number should I define in my config:

sensor:
  - platform: pulse_counter
    pin:
      number: XX??
      mode:
        input: true
        pullup: true


 and which actual pin on the board that will be? (I suspect either GPIO 01, 02 or 03??)

Thanks