#include <bits/stdc++.h>
using namespace std;
int main(void){
    int n,m,q;
    cin>>n>>m>>q;
    vector<vector<array<int,2>>>parent(n),ans(n);
    vector<vector<int>>d(n);
    vector<set<int>>s(n);
    for(int i=0;i<n;i++){
        int a;
        cin>>a;
        parent[i].push_back({0,i});
        ans[i].push_back({0,1});
        d[i].push_back(i);
        s[i].insert(a);
    }
    vector<array<int,3>>edge(m);
    for(int i=0;i<m;i++){
        cin>>edge[i][1]>>edge[i][2]>>edge[i][0];
        edge[i][1]--,edge[i][2]--;
    }
    sort(edge.begin(),edge.end());
    vector<int>xs;
    xs.push_back(0);
    for(auto &x:edge){
        int p1=parent[x[1]][(int)parent[x[1]].size()-1][1],p2=parent[x[2]][(int)parent[x[2]].size()-1][1];
        if(p1==p2)continue;
        xs.push_back(x[0]);
        if(d[p1].size()>d[p2].size())swap(p1,p2);
        for(auto &y:d[p1]){
            d[p2].push_back(y);
            parent[y].push_back({x[0],p2});
        }
        for(auto &y:s[p1]){
            s[p2].insert(y);
        }
        ans[p2].push_back({x[0],(int)s[p2].size()});
    }
    while(q--){
        int now,c;
        cin>>now>>c;
        now--;
        int mn=0,mx=xs.size();
        while(mx-mn){
            int mid=(mx+mn)/2;
            int val=xs[mid];
            auto iter=lower_bound(parent[now].begin(), parent[now].end(),(array<int,2>){val+1,-1});
            int pos = iter-parent[now].begin()-1;
            int par=parent[now][pos][1];
            iter=lower_bound(ans[par].begin(), ans[par].end(),(array<int,2>){val+1,-1});
            pos=iter-ans[par].begin()-1;
            if(ans[par][pos][1]>=c){
                mx=mid;
            }else{
                mn=mid+1;
            }
        }
        cout<<(mx==xs.size()?-1:xs[mx])<<endl;
    }
    return 0;
}