I've removed/deleted Keychain Access by an accident, how can i get it back?

I didn't know what I was doing. I got very angry on the POp-up "write in password to Key login" everytime i opened a program. And by an accident i drag the Keychain acces to the trash and removed all of the trash... and now, the program is gone.. How can i get rid of the Pop-ups? it keeps p!popping" up! 😟 Did i need the program anyways?