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

const int NMAX = 1010, MMAX = 10010;

int N, M, Source, Sink, X[MMAX], Y[MMAX], Z[MMAX], Cap[NMAX][NMAX], Flow[NMAX][NMAX], Father[NMAX];
vector<int> G[NMAX];
bool Used[NMAX], VisSource[NMAX], VisSink[NMAX];

bool BFS()
{
    for(int i = 1; i <= N; ++ i)
        Used[i] = Father[i] = 0;
    queue<int> Q;
    Q.push(Source);

    Used[Source] = 1;

    while(!Q.empty())
    {
        int Node = Q.front();
        Q.pop();
        if(Node == Sink) continue;

        for(int i = 0; i < G[Node].size(); ++ i)
        {
            int Vec = G[Node][i];
            if(!Used[Vec] && Cap[Node][Vec] > Flow[Node][Vec])
            {
                Used[Vec] = 1;
                Father[Vec] = Node;
                Q.push(Vec);
            }
        }
    }
    return Used[Sink];
}

void MaxFlow()
{
    while(BFS())
    {
        for(int i = 0; i < G[Sink].size(); ++ i)
        {
            int Vec = G[Sink][i];
            if(Used[Vec] && Cap[Vec][Sink] != Flow[Vec][Sink])
            {
                Father[Sink] = Vec;
                int MinF = 0x3f3f3f3f;
                for(int Node = Sink; Node != Source; Node = Father[Node])
                    MinF = min(MinF, Cap[Father[Node]][Node] - Flow[Father[Node]][Node]);

                for(int Node = Sink; Node != Source; Node = Father[Node])
                {
                    Flow[Father[Node]][Node] += MinF;
                    Flow[Node][Father[Node]] -= MinF;
                }
            }
        }
    }
}

void Mark(bool Vis[NMAX], int Node)
{
    Vis[Node] = 1;
    for(int i = 0; i < G[Node].size(); ++ i)
    {
        int Vec = G[Node][i];
        if(!Vis[Vec] && Cap[Node][Vec] > Flow[Node][Vec] && Cap[Vec][Node] > Flow[Vec][Node])
            Mark(Vis, Vec);
    }
}

int main()
{
    freopen("critice.in", "r", stdin);
    freopen("critice.out", "w", stdout);

    scanf("%i %i", &N, &M);
    for(int i = 1; i <= M; ++ i)
    {
        scanf("%i %i %i", &X[i], &Y[i], &Z[i]);
        Cap[X[i]][Y[i]] = Cap[Y[i]][X[i]] = Z[i];
        G[X[i]].push_back(Y[i]);
        G[Y[i]].push_back(X[i]);
    }

    Source = 1; Sink = N;
    MaxFlow();
    Mark(VisSource, Source);
    Mark(VisSink, Sink);

    vector<int> Res;
    for(int i = 1; i <= M; ++ i)
        if((VisSource[X[i]] && VisSink[Y[i]]) || (VisSource[Y[i]] && VisSink[X[i]]))
            Res.push_back(i);

    printf("%i\n", Res.size());
    for(int i = 0; i < Res.size(); ++ i)
        printf("%i\n", Res[i]);
}