#include<stdio.h>
#include<vector>
#include<cstdlib>
#define dim 104
using namespace std;

bool state[dim];
class ecuations
{
public:
	int x, y, z;
	bool ok;

	void updateOk()
	{
		switch (z)
		{
		case 0:
			ok = state[x] || state[y];
			break;
		case 1:
			ok = state[x] || !state[y];
			break;
		case 2:
			ok = !state[x] || state[y];
			break;
		default:
			ok = !state[x] || !state[y];
		}
	}
	ecuations(int X, int Y, int Z)
	{
		x = X;
		y = Y;
		z = Z;
	}

};
vector<ecuations> v;
bool satisfied(int m)
{
	for (int i = 0; i < m; ++i)
	{
		v[i].updateOk();
		if (!v[i].ok)
		{
			bool aux = rand() % 2;
			if (aux)
				state[v[i].x] = !state[v[i].x];
			else
				state[v[i].y] = !state[v[i].y];

			return false;
		}

	}
	return true;
}

int main()
{

	FILE*f = fopen("party.in", "r");
	int n, m;
	fscanf(f, "%d %d", &n, &m);
	for (int i = 1; i <= m; ++i)
	{
		int x, y, z;
		fscanf(f, "%d%d%d", &x, &y, &z);
		ecuations ec(x, y, z);
		v.push_back(ec);
	}
	fclose(f);


	for (int i = 1; i <= n; ++i)
		state[i] = rand() % 2;



	while (!satisfied(m));

	int nr = 0;
	for (int i = 1; i <= n; ++i)
		nr += state[i];

	FILE*g = fopen("party.out", "w");
	fprintf(g, "%d\n", nr);
	for (int i = 1; i <= n; ++i)
	{
		if (state[i])
			fprintf(g, "%d\n", i);
	}

	return 0;
}