Login, excute command, logout Script Help

Good Evening all,
After spending the last week or so reading many posts I decided to register and join in. This is my first post on the forum so please forgive me as im new to this, Im after some help in throwing together a quick basic script without using expect to change the password on several routers.

All i need to do is below

ssh username@hostname

then you will be prompted for a password so the script needs to enter the password.

Commands that need entering

password change

then you will be prompted for current password so script to enter current password

you will then be prompted to enter new password so again script to enter

then you are requested to confirm the password again.

logout then start over again on the next router.

unfortunatly i am unable to create password less login either...

Any help you guys can offer would be very much appreciated.

Thanks