Hey New here on the forum. I have a small problem with some contrapositive proofs..

I have to make a contrapositive proof that:

∀x, y ∈ R : x · y < 1 ⇒ x < 1 ∨ y < 1

I can logically see what I'm supposed to do.. and that the statement is correct.. but how do i prove it?? I know that the normal way is to prove that .. but I'm a little stuck from there.. anyone here who can help?