Let A B C D E be a convex pentagon with \overline{A B}\|\overline{C E}, \overline{B C}\| \overline{A D}, \overline{A C} \| \overline{D E}, \angle A B C=120^{\circ}, A B=3, B C=5, and D E=15. Given that the ratio between the area of \triangle A B C and the area of \triangle E B D is m / n, where m and n are relatively prime positive integers, find m+n.