#include<cstdio>
#include<cstdlib>
#include<ctime>
#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;

const int NMAX = 1010;
const int MMAX = 10010;

int N, M;
int Bl[MMAX][4];
int val[NMAX];

void citire()
{
	cin >> N >> M;
	for(int i = 1 ; i <= M ; i++)
		cin >> Bl[i][1] >> Bl[i][2] >> Bl[i][0];
}

bool corect(int rel, int x, int y)
{
	switch(rel)
	{
	case 0:	return(x || y);
	case 1:	return(x || (!x && !y));
	case 2:	return(y || (!y && !x));
	case 3:	return(!x || !y);
	}
}

bool dif_zero()
{
	for(int i = 1 ; i <= N ; i++)
		if(val[i])
			return 1;
	return 0;
}

void rezolva()
{
	int gasit, esuat;
	srand(time(NULL));
	for(int i = 1 ; i <= N ; i++)
		val[i] = rand()%2;
	for(int i = 1 ; i <= 50 * N ; i++)
	{
		gasit = 1; esuat = 1;
		for(int j = 1 ; j <= M ; j++)
			if(!corect(Bl[j][0], val[Bl[j][1]], val[Bl[j][2]]))
			{
				gasit = 0;
				esuat = j;
				break;
			}
		if(gasit == 1 && dif_zero())
			return;
		if(rand() % 2 + 1 == 1)
			val[Bl[esuat][1]] ^= 1;
		else
			val[Bl[esuat][2]] ^= 1;
	}
	//printf("TEAPA");
}

void scriere()
{
	int NR = 0;
	for(int i = 1 ; i <= N ; i++)
		if(val[i])
			NR++;
	printf("%d\n", NR);
	for(int i = 1 ; i <= N ; i++)
		if(val[i])
			printf("%d\n", i);
}

int main()
{
	freopen("party.in", "r", stdin);
	freopen("party.out", "w", stdout);
	citire();
	rezolva();
	scriere();
	return 0;
}