The next three letters in this sequence follow by days of the week. S is sunday, m is monday t is tuesday, w is wednesday, so the next three letters are tfs because thursday friday saturday.
Sunday Monday Tuesday wednesday
Sunday monday tuesday wednesday
I think it stands for sunday monday tuesday wednessday?
Sunday Monday tuesday wednesday
Tfs Because smtw stands for sunday, Monday, Tuesday, and Wednesday. So tfs stands for Thursday, Friday, and saturday.