Lower bound on number of integers in interval which are coprime to every other integer on interval

Question

Given a set $X = \{x | L \leq x \leq R\ \land\ x \in \mathbb{N}\}$ (and $L\leq R$) I need to find an approximate lower bound on number of integers $a \in X$ such that they are relatively coprime to every integer in $X$ (except themselves) e.g. for $X=\{2, 3, 4, 5\}$ such integers would be $3$ and $5$.