#include<fstream>
#include<stdlib.h>
#include<time.h>
using namespace std;

ifstream fin("party.in");
ofstream fout("party.out");

#define NMAFirst_friends 102
#define MMAFirst_friends 1002

int N, M;
bool Friends[NMAFirst_friends];
struct Relation {int type, First_friends, y;};
Relation R[MMAFirst_friends];
void read(){
    fin >> N >>M;
    for(int i = 1; i <= M; i++)
        R[i].First_friends >> R[i].y >> R[i].type;

}
bool verifica(int i, bool a, bool b){

    if(R[i].type == 0) return a || b;

    if(R[i].type == 1) return !(!a && b);

    if(R[i].type == 2) return !(a && !b);

    if(R[i].type == 1) return !a || !b;



}
int main(){
    read();

    srand(time(NULL));
    int Number_Friends = 1 + rand() % N;

    for(int i = 1; i <= Number_Friends; i++){
        int First_friends = rand() % N + 1;
        Friends[First_friends] = true;
    }
    for(int i = 1; i <= M; i++)
        if(!verifica(i, Friends[R[i].First_friends] , Friends[R[i].y])){
            int r = rand() % 2;
            if(r) Friends[R[i].First_friends] = !Friends[R[i].First_friends];
            else  Friends[R[i].y] = !Friends[R[i].y];

            i = 0;
        }
     Number_Friends = 0;
    for(int i = 1; i <= N; i++)
        if(Friends[i] == true)
            Number_Friends++;

    fout <<Number_Friends <<'\n';

    for(int i = 1; i <= N; i++)
        if(Friends[i] == true)
            fout << i <<'\n';

    return 0;
}