MS Word: how do I type an equation involving letters above/below an arrow?

I am trying to reproduce the following in MS Word 2016. That is, letters above and below an arrow. Does anyone know how I can achieve this?

this


Type -> in the equation editor. It will give you an arrow. Then type \above. Then when you press the space bar, the equation editor will give you the space to write on above the arrow. Similarly, when you type \below followed by a press on the space bar, you will find the slot to write under the arrow.