The nearest convenience store

Yeongseon is looking for a new home. She lives alone and eats at a convenience store on most days, so she wants the home whose distance to a convenience store is the smallest.

The city is given as vertices and edges. Every home candidate and every convenience store sits on a vertex. The distance of a home candidate is the length of the shortest path from that candidate to the nearest convenience store.

Yeongseon is busy preparing for a camp she teaches at, so pick the home for her. If several candidates have the same distance, pick the one with the smallest vertex number.

The first line contains the number of vertices $n$ and the number of edges $m$. ($2 \le n \le 5000$, $1 \le m \le 100000$)

Each of the next $m$ lines contains $a$, $b$ and $c$, which means the edge joining vertex $a$ and vertex $b$ has length $c$. ($1 \le a, b \le n$, $1 \le c \le 10000$) Several edges may join the same pair of vertices, and an edge may have $a$ equal to $b$. Edges have no direction.

The next line contains the number of home candidates $p$ and the number of convenience stores $q$. ($1 \le p$, $1 \le q$, $2 \le p + q \le n$)

The next line contains the $p$ vertex numbers of the home candidates, and the line after that contains the $q$ vertex numbers of the convenience stores. No number appears twice on the same line, and no vertex is both a home candidate and a convenience store.

A home candidate may be unable to reach any convenience store. Such a candidate is never picked. At least one home candidate can reach a convenience store.

Print, on one line, the vertex number of the home candidate whose distance to a convenience store is the smallest. If several candidates have the same distance, print the smallest vertex number.