#include<iostream>
using namespace std;
#define INF 10001
#define M 3000
struct
{
    int begin;
    int end;
    int num;
}edge[M*2];
int dis[M], i, j; 
bool BellmanFord(int alldots, int start, int alledges)
{
    for(i=0; i<alldots; i++) //初始化dis[]
        dis[i] = INF;
    dis[start] = 0;  //原點的最短距離初始化為0
    for(i=0; i<alldots-1; i++)
        for(j=0; j<alledges; j++) //雙向遍歷或者單向遍歷每條邊,這要看這條邊是否為雙向的了
            if(dis[edge[j].end] > dis[edge[j].begin]+edge[j].num) 
                dis[edge[j].end] = dis[edge[j].begin]+edge[j].num;
    for(i=0; i<alledges; i++) //判斷是否存在負環
        if(dis[edge[i].end] > dis[edge[i].begin]+edge[i].num)
            return true;  //存在負環
    return false;  //不存在負環
}
int main()
{
    int Case, alldots, numofedge, w, e, x, y, z;
    cin>>Case;
    while(Case--)
    {
        e = 0;
        cin>>alldots>>numofedge>>w;
        for(i=0; i<numofedge; i++)
        {
            cin>>x>>y>>z;
            edge[e].begin = x;
            edge[e].end = y;
            edge[e++].num = z;
            edge[e].begin = y;
            edge[e].end = x;
            edge[e++].num = z;
        }
        for(i=0; i<w; i++)
        {
            cin>>x>>y>>z;
            edge[e].begin = x;
            edge[e].end = y;
            edge[e++].num = -z;
        }
        if(BellmanFord(alldots, 1, e))
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
    }
}