Q: i don't have none of the pc with me,now please tel me how to deauthorize all the computers

presently i'm using 5s but  i want to upgrade my mobile, while i'm trying to take the back at my pc ,it showing authorize to this computer,while i'm trying to take the back its showing unable to do that, due to already authorize 5 computers,but currently  i don't have none of the pc with me,please tel me now how will i make all this computers deauthorize now,,,,,,,,