# 部分点1

import heapq

N,M,Q = map(int, input().split())

A = list(map(int, input().split()))
A = [x-1 for x in A]

G = [[] for _ in range(N)]

for i in range(M):
    u,v,w = map(int, input().split())
    G[u-1].append((v-1,w))
    G[v-1].append((u-1,w))


hq = []

start=0 # s=1より始点は0 (0-indexedで管理)
dist = [10**9+1]*N
dist[start]=0

heapq.heappush(hq,(0,start))

while hq:
    m,p = heapq.heappop(hq)
    if dist[p]!=m:
        continue

    for nex,w in G[p]:
        if (max(m,w)<dist[nex]):
            dist[nex]=max(m,w)
            heapq.heappush(hq,(dist[nex],nex))

ans=[10**9+1]*N
for i in range(N):
    ans[A[i]]=min(ans[A[i]],dist[i])

ans=sorted(ans)

for _ in range(Q):
    s,c = map(int, input().split()) # s=1

    if ans[c-1]==10**9+1:
        print(-1)
    else:
        print(ans[c-1])