#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include <cmath>

 #include<stack>

 #include<vector>

 #include<map>

 #include<set>

 #include<queue>

 #include<algorithm>

 using namespace std;

 typedef long long LL;

 const int INF = (<<)-;

 const int maxn=;

 int d[maxn];

 int flag;

 int nodenum,edgenum,ecnt;

 struct Edge{

     int u,v,cost;

 } e[maxn];

 int Bellman_ford(){

     for(int i=;i<=nodenum;i++) d[i]=INF;

     d[]=;

     for(int i=;i<nodenum;i++){

         for(int j=;j<=ecnt;j++){

             if(d[e[j].v]>d[e[j].u]+e[j].cost)

             d[e[j].v]=d[e[j].u]+e[j].cost;

         }

     }

     flag=;

     for(int i=;i<=ecnt;i++){

         if(d[e[i].v]>d[e[i].u]+e[i].cost){

             flag=;

             break;

         }

     }

     return flag;

 }

 void addedges(int a,int b,int c){

     e[++ecnt].u=a;

     e[ecnt].v=b;

     e[ecnt].cost=c;

 }

 int main(){

     int m,w,ncase;

     int a,b,c;

     scanf("%d",&ncase);

     while(ncase--){

         ecnt=;

         scanf("%d %d %d",&nodenum,&m,&w);

         while(m--){

             scanf("%d %d %d",&a,&b,&c);

             addedges(a,b,c);

             addedges(b,a,c);

         }

         while(w--){

             scanf("%d %d %d",&a,&b,&c);

             c=-c;

             addedges(a,b,c);

         }

         if(Bellman_ford()) printf("NO\n");

         else printf("YES\n");

     }

     return ;

 }