Tensor contraction exercsie

I am working on a "tensor gymnastics" exercise, and have arrived at the following line to simplify:

$$\delta_{ik} y^{i} X_{ij}$$

where $$\delta_{ik}$$ is the Kroenecker delta. Does this simplify to:

$$y^{k} X_{kj}$$, i.e., replace all of the $$i's$$ with $$k's$$, or just apply to one of the $$y^i$$ or $$X_{ij}$$?

Thank you.