I am unable to link my FB contacts to my Iphone5 (purchased today),

When I go into the FaceBook APP, click on the friends option, and then the button in the top right, i dont have an option to sync contacts like other people seem to be able to do.

I have also tried to link contacts up by using SETTINGS>FACEBOOK>UPDATE ALL CONTACTS, still no luck.

HELP PLEASE

I have a 16Gb White Iphone5