#include <map>

#include <set>

#include <list>

#include <cmath>

#include <ctime>

#include <deque>

#include <stack>

#include <queue>

#include <cctype>

#include <cstdio>

#include <string>

#include <vector>

#include <climits>

#include <cstdlib>

#include <cstring>

#include <iostream>

#include <algorithm>

#define LL long long

#define PI 3.1415926535897932626

using namespace std;

int gcd(int a, int b) {return a % b ==  ? b : gcd(b, a % b);}

#define MAXN 1010

int p[MAXN];

int Find(int x) {return x == p[x] ? x : p[x] = Find(p[x]);}

int N,M,R;

struct node

{

        int u,v,w;

        friend bool operator < (const node &a,const node &b)

        {

                return a.w < b.w;

        }

}src[MAXN * MAXN];

bool judge(int s,int t)

{

        int x =Find(s);

        int y = Find(t);

        if (x == y) return true;

        return false;

}

bool query(int s,int t,int least)

{

        for (int i =  ; i < M ; i++)

        {

                if (src[i].w < least) continue;

                int x = Find(src[i].u), y = Find(src[i].v);

                if (x != y) p[x] = y;

                if (judge(s,t))

                {

                        return true;

                }

        }

        return false;

}

int main()

{

     int kase = ;

     while (cin >> N >> M >> R)

     {

             cout << "Case " << kase++  << ':' << endl;

             for (int i =  ; i < M ;i++)

                cin >> src[i].u >> src[i].v >> src[i].w;

             for (int i =  ; i < R; i++)

             {

                     int u ,v,w;

                     for (int i =  ;i <= N ; i++) p[i] = i;

                     cin >> u >> v  >> w;

                     if (query(u,v,w)) puts("yes");

                     else puts("no");

             }

     }

     return ;

}