#include <bits/stdc++.h>
#define int long long  
using namespace std;

inline int read()
{
	int sum=0,ff=1; char ch=getchar();
	while(!isdigit(ch))
	{
		if(ch=='-') ff=-1;
		ch=getchar();
	}
	while(isdigit(ch))
		sum=sum*10+(ch^48),ch=getchar();
	return sum*ff;
}


const int N=1e5+5;

int n,m,fa[N],tot,al,T,ask;

struct nood
{
	int u,v,op;
};
nood e[N<<1];

inline int find(int x)
{
	if(x==fa[x]) return x;
	return fa[x]=find(fa[x]);
}

inline void sub_tree()
{
	if(m<n-1)
		printf("No\n");
	if(ask==T) 
		printf("Yes\n");
	else printf("No\n");
	exit(0);
}

signed main()
{
	n=read();
	m=read();
	T=read();
	for ( int i=0;i<=n;i++ ) fa[i]=i;
	for ( int i=1;i<=T;i++ )
	{
		e[i]=(nood){read(),read(),read()};
		if(!e[i].op)
		{
			ask++;
			int x=find(e[i].u),y=find(e[i].v);
			if(x==y) continue;
			al++; 
			fa[x]=y;
		}
	}
	if(m<=n-1) sub_tree();
	for ( int i=1;i<=T;i++ ) 
	{
		if(e[i].op)
		{
			int x=find(e[i].u),y=find(e[i].v);
			if(x==y) return printf("No\n"),0;
		}
	}
	tot=n-al;
	int l=n,r=al+(tot*(tot-1))/2;
//	cout<<m<<" "<<r<<endl;
	if(m>=l&&m<=r) printf("Yes\n");
	else printf("No\n");
	return 0;
}