In trapezoid $${ABCD}$$ with $$\overline{BC}\parallel\overline{AD}$$, let $${BC}$$ = $${1000}$$ and $${AD}$$ = $${2008}$$. Let $$\angle{A}$$ = $$37^{\circ}$$, $$\angle {D}$$ = $$53^{\circ}$$, and $${M}$$ and $${N}$$ be the midpoints of $$\overline{BC}$$ and $$\overline{AD}$$, respectively. Find the length $${MN}$$.