#include <bits/stdc++.h>
using namespace std;
int t,mp[1001][1001];
int n,m,w;
bool floyd() {
	for(int i=1; i<=n; i++) {
		for(int j=1; j<=n; j++) {
			for(int k=1; k<=n; k++) {
				mp[i][j]=min(mp[i][j],mp[i][k]+mp[k][j]);
				if(mp[i][i]<0) return false;
			}
		}
	}
	return true;
}
int main() {
	//freopen("wormhole.in","r",stdin);
	//freopen("wormhole.out","w",stdout);
	cin>>t;
	while(t--) {
		memset(mp,0x3f,sizeof(mp));
		cin>>n>>m>>w;
		while(m--) {
			int u,v,c;
			scanf("%d%d%d",&u,&v,&c);
			mp[u][v]=mp[v][u]=c;
		}
		while(w--) {
			int u,v,c;
			scanf("%d%d%d",&u,&v,&c);
			mp[u][v]=-c;
		}
		if(!floyd()) {
			cout<<"YES\n";
		} else {
			cout<<"NO\n";
		}
	}
	return 0;
}

https://www.luogu.com.cn/record/137083074