Standard equation of hyperbola - class-XI

Consider
the set of hyperbola $xy = {\text{ }}K,{\text{ K}} \in {\text{R,}}$  let ${e _1}$  be eccentricity
when $K = \sqrt {2017} $  and ${e _2}$ be the
eccentricity when $K = \sqrt {2018} $ , then ${e _1} = {e _2}$   is equal to