#include <fstream>
#include <algorithm>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <iostream>
#include <string.h>
#include <vector>
using namespace std;
#define MAX_N 2000

int v[MAX_N], x[MAX_N], y[MAX_N], c[MAX_N];

int valid(int i)
{
	switch(c[i])
	{
		case 0: return v[x[i]] || v[y[i]]; break;
		case 1: return v[x[i]] || !v[y[i]]; break;
		case 2: return v[y[i]] || !v[x[i]]; break;
		case 3: return v[x[i]]+v[y[i]] != 2;
	}
	return 1;
}

void random(int i)
{
	int r = rand()%2; r++;
	if(r == 1)
		v[x[i]] = !v[x[i]];
	if(r == 2)
		v[y[i]] = !v[y[i]];
}

int main()
{
	ifstream in("party.in");
	ofstream out("party.out");
	
	int i, n, m, nr=0;
	
	//Read
	in>>n>>m;
	for(i=1; i<=n; i++)
		in>>x[i]>>y[i]>>c[i];
		
	//Compute
	for(i=1; i<=n; i++)
		v[i] = 1;
	while(1)
	{
		for(i=1; i<=m; i++)
			if(valid(i) == 0)
			{
				random(i);
				break;
			}
		if(i == m+1)
			break;
	}
	
	//Print
	for(i=1; i<=n; i++)
		if(v[i])
			nr++;
	out<<nr<<'\n';
	for(i=1; i<=n; i++)
		if(v[i])
			out<<i<<'\n';
}