oj 1216

#include<bits/stdc++.h>
using namespace std;
const int maxn = 200090;
queue <int > q;

int f;
int vv[maxn];
int d[maxn];
int v[maxn];
int n,m,tot = 0,flag = 0,w;
int head[maxn];
struct node {
	int fr,Next,ver,value;
};
node edge[maxn];

inline int Read () {
	int xx = 0;
	int ff = 1;
	char ch = getchar();
	while (ch > '9' || ch < '0') {
		if (ch == '-') {
			ff = -1;
		}
		ch = getchar();
	}
	while (ch <= '9' && ch >= '0') {
		xx = (xx << 1) + (xx << 3) + ch - '0';
		ch = getchar();
	}
	return xx * ff;
}
inline void add (int x,int y,int z) {
	edge[++tot].fr = x;
	edge[tot].Next = head[x];
	edge[tot].ver = y;
	edge[tot].value = z;
	head[x] = tot;
}
inline void spfa() {
	d[1] = 0;
	v[1] = 0;
	q.push(1);
	while (!q.empty()) {
		int x = q.front();
		q.pop();
		v[x] = 0;
		for (int i = head[x];i;i = edge[i].Next) {
			int y = edge[i].ver; int z = edge[i].value;
			if (d[x] + z < d[y]) {
				d[y] = d[x] + z;
				vv[y]++;
				if (vv[y] >= n)  {
					flag = 1;
					return ;
				}
				if (v[y] != 1) q.push(y),v[y] = 1;
			}
		}
	}
}

int main () {
	f = Read();
	while (f--) {
		flag = 0;
		memset(head,0,sizeof(head));
		memset(v,0,sizeof(v));
		memset(vv,0,sizeof(vv));
		n = Read(); m = Read(); w = Read();
		for (int i = 1;i <= n;i++) d[i] = 1e9;
		for (int i = 1;i <= m;i++) {
			int a = Read();
			int b = Read();
			int c = Read();
			add (a,b,c); add (b,a,c);
		}
		for (int i = 1;i <= w;i++) {
			int a = Read();
			int b = Read();
			int c = Read();
			add(a,b,-c);
		}
		spfa();
		if (flag == 1) printf("YES ");
		else printf("NO ");
	}
	return 0;
}