#include <fstream>
#include <vector>
#include <string.h>

#define nMax 235
#define pb push_back

using namespace std;
ifstream fin("party.in");
ofstream fout("party.out");
int variables, expressions;
int value[nMax], discover[nMax], viz[nMax], Sol[nMax];
vector<int> G[nMax], GT[nMax];
inline int non(int x)
{
    return (x>variables) ? x-variables : x+variables;
}
void sau(int x, int y)
{
    G[non(x)].pb(y);
    GT[y].pb(non(x));
    G[non(y)].pb(x);
    GT[x].pb(non(y));
}
void read()
{
    int x, y, z;
    fin>>variables>>expressions;

    for(int i=1;i<=expressions;i++)
    {
        fin>>x>>y>>z;

        switch(z)
        {
            case 0:sau(x, y); break;
            case 1:sau(x, non(y)); break;
            case 2:sau(non(x), y); break;
            case 3:sau(non(x), non(y)); break;
        };
    }
}
void dfs(int node)
{
    viz[node]=1;

    for(vector<int>::iterator it=G[node].begin();it!=G[node].end();it++)
    {
        int fiu=*it;
        if(!viz[fiu])
            dfs(fiu);
    }

    discover[++discover[0]]=node;
}
void dfst(int node)
{
    viz[node]=0;
    value[non(node)]=1;

    for(vector<int>::iterator it=GT[node].begin();it!=GT[node].end();it++)
    {
        int fiu=*it;
        if(viz[fiu])
            dfst(fiu);
    }
}
void _2sat()
{
    for(int i=1;i<=2*variables;i++)
        if(!viz[i])
            dfs(i);

    for(int i=discover[0];i>=1;i--)
        if(viz[discover[i]] && viz[non(discover[i])])
            dfst(discover[i]);
}
void write()
{
    for(int i=1;i<=variables;i++)
        if(value[i])
            Sol[++Sol[0]]=i;

    for(int i=0;i<=Sol[0];i++)
        fout<<Sol[i]<<'\n';
}
int main()
{
    read();
    _2sat();
    write();
    return 0;
}