#include "bits/stdc++.h"
#define YES "Yes"
#define NO "No"
#define YESNO OUT(three(solve(),YES,NO))
#define ECHO OUT(solve())
#define three(A,B,C) ((A)?(B):(C))
#define FOR(i,a,b)  for(LL i=(a);i< (LL)(b);i++)
#define EFOR(i,a,b) for(LL i=(a);i<=(LL)(b);i++)
#define RFOR(i,a,b) for(LL i=(b);i>=(LL)(a);i--)
#define REP(i,b) FOR(i,zero,b)
#define rep REP
#define EREP(i,b) EFOR(i,zero,b)
#define RREP(i,b) RFOR(i,b,zero)
#define ALL(c) c.begin(),c.end()
#define UNIQUE(c) sort(ALL(c));c.erase(unique(ALL(c)),c.end())
#define MAX(c) (*max_element(ALL(c)))
#define MIN(c) (*min_element(ALL(c)))
#define MP make_pair
#define FI first
#define SE second
#define SI(x) (LL(x.size()))
#define PB push_back
#define DEBUG(a) OUT(a)
#define DEBUG2(a,b) OUT2(a,b)
#define cat cout << __LINE__ << endl
#define OUT(a) cout << (a) << endl
#define OUT2(a,b) cout << (a) <<" "<<(b) << endl
#define zero 0LL
#define all ALL
#define pb emplace_back
#define eb pb
#define int long long
using namespace std;
template<typename T> inline void maximize(T &a, T b) { a = max(a, b); }
template<typename T> inline void minimize(T &a, T b) { a = min(a, b); }
template<typename T> inline bool middle(T a, T b, T c) { return b <= a && a <= c; }
template<class T> inline bool MX(T &l, const T &r) { return l < r ? l = r, 1 : 0; }
template<class T> inline bool MN(T &l, const T &r) { return l > r ? l = r, 1 : 0; }
typedef int LL;
typedef double ld;
typedef int ut;
typedef vector<ut> VI;
typedef vector<VI> VII;
typedef pair<ut, ut> pr;
typedef pair<ut, pr> ppr;
typedef vector<pr> Vpr;
typedef vector<ppr> Vppr;
typedef tuple<int, int, int, int> tapu;
typedef vector<tapu> Vtapu;
typedef priority_queue<tapu, Vtapu, greater<tapu> > PQ;
inline void outputVI(VI x) { REP(i, SI(x)) { cout << three(i, " ", "") << x[i]; }OUT(""); }
const int SIZE1 = 3e5 + 1000;
const int SIZE2 = 5010;
const int SIZE3 = 430;
const int SIZE = SIZE1;
const int MAPSIZE = 40;
const LL p = 7 + 1e9;
const LL INF = 1LL << 60;
const long double EPS = 1e-7;
typedef pair<ld, ut> pld;
 class UnionFind{
 
	vector<int> unions,talls,sents,dists,sizes;
	int size;
public:
	UnionFind(){}
	UnionFind(int size):size(size){
		init();
	}
	void init(){
	 	unions=vector<int>(size);
	 	talls=vector<int>(size);
	 	sents=vector<int>(size);
	 	dists=vector<int>(size);
	 	sizes=vector<int>(size);
		FOR(i,0,size){
			unions[i]=i;
			sents[i]=0;
			sizes[i]=1;
//			ns[i].PB(pr(0,1));
			talls[i]=1;
		}
	}
	int find(int x,int t=0){
		if(unions[x]==x || sents[x]>t) return x;
		return find(unions[x],t);
 
	}
	int minisize(int x){
		if(x==unions[x]) return sizes[x];
		return minisize(find(x));
	}
	bool isFriend(int a,int b,int t=0){
		return find(a,t)==find(b,t);	
	}
	void unite(int a,int b,int t=0){
		if(isFriend(a,b,t)) return;
		a=find(a,t);
		b=find(b,t);
		if(talls[a]<talls[b]) unite(b,a,t);
		else{
 			sizes[a]+=sizes[b];
			sents[b]=t;
			talls[a]=max(talls[a],talls[b]+1);
			unions[b]=a;
			dists[b]=1;
//			ns[a].PB(pr(t,ns[b].back().second+ns[a].back().second));
		}
	}
};
LL N,Q,M;
UnionFind uf(SIZE);
LL A[SIZE],B[SIZE],C[SIZE];
LL solve(){
	cin >> N >> M >> Q;
	Vpr vs[2];
	REP(i,Q){
		LL a,b;
		cin >> a >> b >> C[i];
		vs[C[i]].pb(a,b);
	}
	REP(j,2)
		REP(i,vs[j].size()){
			C[i]=j;
			A[i]=vs[j][i].first;
			B[i]=vs[j][i].second;		
			if(C[i]==1 and M==N-1) return 0; 
			if(C[i]==0) uf.unite(A[i],B[i]);
			if(uf.isFriend(A[i],B[i]) and C[i]==1) return 0;
		}
	if(M==N-1) return 1;
	LL counts=0;
	REP(i,N) if(uf.find(i)==i) counts++;
	counts--;
	return (M-(N-1))<=counts*(counts-1)/2;
}
signed main(){
  YESNO;
  return 0;
}


Measured memory_bytes: 18928