#include <iostream>
#include <vector>
using namespace std;
int F,N,M,W;
const int INF=1<<30;
struct Edge {
    int s,e,w;
    Edge(int ss,int ee,int ww):s(ss),e(ee),w(ww) {}
    Edge() {}
};
vector<Edge> edges;
int dist[1000];
int Bellman_ford(int v) {
    for(int i=1; i<=N; ++i)
        dist[i]=INF;
    dist[v]=0;
    for(int k=1; k<N; ++k) {
        for(int i=0; i<edges.size(); ++i) {
            int s=edges[i].s;
            int e=edges[i].e;
            if(dist[s]+edges[i].w<dist[e])
                dist[e]=dist[s]+edges[i].w;
        }
    }
    for(int i=0; i<edges.size(); ++i) {
        int s=edges[i].s;
        int e=edges[i].e;
        if(dist[s]+edges[i].w<dist[e])
            return true;
    }
    return false;

}
int main() {
    cin >> F;
    while(F--) {
        edges.clear();
        cin >> N>>M>>W;
        for(int i=0; i<M; ++i) {
            int s,e,t;
            cin >> s>>e>>t;
            edges.push_back(Edge(s,e,t));
            edges.push_back(Edge(e,s,t));
        }
        for(int i=0; i<W; i++) {
            int s,e,t;
            cin >> s>> e>>t;
            edges.push_back(Edge(s,e,-t));
        }
        if(Bellman_ford(1))
            cout << "YES"<<endl;
        else
            cout << "NO" <<endl;
    }
}