# 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)]
W = {0} # 答えは0かw_jなので、添字で二分探索できる

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))
    W.add(w)

W = sorted(W)

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

    ok=len(W)
    ng=-1
    while(ok-ng>1):
        mid = (ok+ng)//2
        D=W[mid]

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

        que = deque([s])
        
        t=1

        while que and t<c:
            m=que.popleft()

            for nex,w in G[m]:
                if ((w<=D) and visited[nex]==False):
                    visited[nex]=True
                    que.append(nex)                
                    if not flag[A[nex]]:
                        flag[A[nex]]=True
                        t+=1
                        if t>=c:
                            break
                        

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

    if ok == len(W):
        print(-1)
    else:
        print(W[ok])