How can I change the inserter to default to imperial system on the canon v900's?

For the canon v900, when I put something into the inserter, then I go to the screen to select the weight and size, when i get to the size, it by default is on european a4/a5 etc, so i have to press to change to us imperial and then select letter size.

On the other v900's they are already set to where when i put the inserter, its already on imperial us and i just have to select the size.

My question is, where in the settings do i have to go exactly to set it to where when i put paper into the inserter, it will by default be on the us imperial system, that way i just select letter size, rather then how it is now where i have to press an extra button because its on the european a4/a5 etc.