// AKBAR - Akbar, the great
 
#include<bits/stdc++.h>
#define ll long long int
#define pb push_back
#define vi vector<ll>
#define vb vector<bool>
#define vd vector<double>
#define vc vector<char>
#define vii vector<vi>
#define mp make_pair
#define vpi vector< pair<ll,ll> >
#define take_input freopen("input.txt", "r", stdin)
#define give_output freopen("output.txt", "w", stdout)
#define fastIO ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define fi first
#define se second
#define mod 1000000007
#define min_pql priority_queue< ll, vector<ll>, greater<ll> >
 
using namespace std;
using namespace std::chrono;
 
 
 
bool check(vii &adj, vb &vis, ll n, ll cityn, ll strn){
	queue<ll> q;
	q.push(cityn);
	if(vis[cityn]==true) return true;
	vi level(n+1, 0);
	while(!q.empty()){	
		ll k=q.front();
		q.pop();
		vis[k]=true;
		if(level[k] == strn) return false;
		for(ll i:adj[k]){
			if(!vis[i]){
				level[i] = level[k]+1;
				q.push(i);
				vis[i] = true;
			}else{
				if(level[i]>level[k]) return true;
			}
		}
	}
	return false;
}
 
 
int main(){
	fastIO;
	// take_input;
	// give_output;
	ll t;
	cin >> t;
	vi vans;
	while(t--){
		ll n,r,m;
		cin >> n >> r >> m;
		vii adj(n+1); // adjacency lists
		vpi q(m); // for storing strength and cityn
		// inserting vertices
		for(ll i=0; i<r; i++){
			ll num1, num2;
			cin >> num1 >> num2;
			adj[num1].pb(num2);
			adj[num2].pb(num1);
		}
		// inserting cityn strength
		for(auto &i:q) cin >> i.fi >> i.se;
		vb vis(n+1, false);
		vis[0]= true;
		ll flag=0;
		for(auto i:q){
			flag = check(adj, vis, n, i.fi, i.se);
			if(flag==1) break;
		}
		if(find(vis.begin(), vis.end(), false) != vis.end()) flag=1;
		if(flag==1) vans.pb(0);
		else vans.pb(1);
	}
	for(ll i:vans){
		if(i==0) cout << "NO\n";
		else cout << "YES\n";
	}
}
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