( ̄▽ ̄)"
#include<iostream>
#include<cstdio>
#include<queue>
#include<vector>
#include<cstring>
#include<algorithm>
using namespace std;
const int INF=10e7;
const int MAXN=510;
int f,n,m,w,s,e,t;
int lc[MAXN],cntNode[MAXN];
bool vis[MAXN];
struct edge
{
int v,cost;
}E;
vector<edge> Edge[MAXN];
bool SPFA()
{
queue<int> que;
int u,v,c,len;
for(int i=1;i<=n;i++)
lc[i]=INF,vis[i]=0,cntNode[i]=0;
lc[1]=0;vis[1]=1;cntNode[1]=1;
que.push(1);
while(!que.empty())
{
u=que.front();que.pop();
vis[u]=0;len=Edge[u].size();
for(int i=0;i<len;i++)
{
v=Edge[u][i].v;
c=Edge[u][i].cost;
if(lc[v]>lc[u]+c)
{
lc[v]=lc[u]+c;
if(!vis[v])
{
vis[v]=1;
++cntNode[v];
que.push(v);
if(cntNode[v]>n)
return true;
}
}
}
}
return false;
}
int main()
{
scanf("%d",&f);
while(f--)
{
scanf("%d%d%d",&n,&m,&w);
for(int i=1;i<=n;i++)
Edge[i].clear();
while(m--)
{
scanf("%d%d%d",&s,&e,&t);
E.v=e;E.cost=t;
Edge[s].push_back(E);
E.v=s;E.cost=t;
Edge[e].push_back(E);
}
while(w--)
{
scanf("%d%d%d",&s,&e,&t);
E.v=e;E.cost=-t;
Edge[s].push_back(E);
}
if(SPFA()) printf("YES
");
else printf("NO
");
}
return 0;
}