# 部分点2

import sys
from collections import deque

input = sys.stdin.readline

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))

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

    ok=10**9+1
    ng=-1
    while(ok-ng>1):
        D = (ok+ng)//2

        visited = [0]*N
        flag = [0]*N
        visited[s]=True
        flag[A[s]]=True

        que = deque([s])

        while que:
            m=que.popleft()

            for nex,w in G[m]:
                if ((w<=D) and visited[nex]==False):
                    visited[nex]=True
                    flag[A[nex]]=True
                    que.append(nex)

        t=0
        for l in range(N):
            if flag[l]:
                t+=1

        if t>=c:
            ok=D
        else:
            ng=D

    if ok == 10**9+1:
        print(-1)
    else:
        print(ok)