#include <iostream>
#include <fstream>
using namespace std;
int a[1000][3], n, m;
bool v[100]={0};

void Conditie(int i)
{
    int var = 0, x1, x2, j;
    bool cond = false;
    x1 = a[i][0] - 1;
    x2 = a[i][1] - 1;
    while (cond == false)
    {
        var++;
        switch (a[i][2])
        {
            case 0: if (v[x1] || v[x2]) cond = true; else cond = false; break;
            case 1: if ((v[x1] && v[x2]) || (v[x1] && !v[x2]) || (!v[x1] && !v[x2])) cond = true; else cond = false; break;
            case 2: if (v[x1] || v[x2]) cond = true; else cond = false; break;
            case 3: if (!v[x1] || !v[x2]) cond = true; else cond = false; break;
        }
        if (var == 2 || var == 4) v[x1] = !v[x1];
        else  if (var == 3) {v[x1] = !v[x1]; v[x2] = !v[x2];}
    }
    if (var == 1 && i + 1 < m) Conditie(i+1);
    else if (var != 1) Conditie(0);
}

main()
{
    ifstream f1("test.in");
    ofstream f2("test.out");
    int i, k = 0;
    f1 >> n >> m;
    for (i = 0; i < m; i++)
        f1 >> a[i][0] >> a[i][1] >> a[i][2];
    for (i = 0; i < 100; i++)
        v[i] = true;
    Conditie(0);
    for (i = 0; i < n; i++)
        if (v[i] == true) k++;
    f2 << k << "\n";
    for (i = 0; i < n; i++)
        if (v[i] == true) f2 << i + 1 << "\n";;
}