How do I sync all of my Facebook friends' numbers to my contacts on iPhone with ios7?

[Brandon S]

How do I put all of my Facebook friends' phone numbers on my iPhone with iOS7? When I go to friends in the app the Sync Contacts button isn't there. Help?
Thanks Joe--but I hit sync and everything should've went well, and it said my contacts were synced, but I have no new contacts? Thank you.

[Joe]

if you install the facebook messenger app, there will be a pop up screen that asks you if you want to sync your contacts.
if you already have the messenger app, you probably clicked 'no' before.
in which case all you need to do is uninstall it and re-download.
hope this helps.