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

const int NMAX = 1005, INF = 0x3f3f3f3f;

int N, M, X[10 * NMAX], Y[10 * NMAX], C[10 * NMAX], Cap[NMAX][NMAX], Flow[NMAX][NMAX], Father[NMAX], Source, Sink;
vector<int> G[NMAX];
bool Used[NMAX], SourceBFS[NMAX], SinkBFS[NMAX];

bool BFS()
{
    for(int i = Source; i <= Sink; ++ i) Father[i] = Used[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(vector<int> :: iterator it = G[Node].begin(); it != G[Node].end(); ++ it)
            if(Cap[Node][*it] > Flow[Node][*it] && !Used[*it])
            {
                Used[*it] = 1;
                Father[*it] = Node;
                Q.push(*it);
            }
    }
    return Used[Sink];
}

void GetFlow()
{
    while(BFS())
    {
        for(vector<int> :: iterator it = G[Sink].begin(); it != G[Sink].end(); ++ it)
            if(Used[*it] && Cap[*it][Sink] != Flow[*it][Sink])
            {
                Father[Sink] = *it;
                int MinFlow = INF;
                for(int Node = Sink; Node != Source; Node = Father[Node])
                    MinFlow = min(MinFlow, Cap[Father[Node]][Node] - Flow[Father[Node]][Node]);
                for(int Node = Sink; Node != Source; Node = Father[Node])
                {
                    Flow[Father[Node]][Node] += MinFlow;
                    Flow[Node][Father[Node]] -= MinFlow;
                }
            }
    }
}

void Mark(int Node, bool Used[NMAX])
{
    Used[Node] = 1;
    for(vector<int> :: iterator it = G[Node].begin(); it != G[Node].end(); ++ it)
        if(!Used[*it] && Cap[Node][*it] > Flow[Node][*it] && Cap[*it][Node] > Flow[*it][Node])
            Mark(*it, Used);
}

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], &C[i]);
        G[X[i]].push_back(Y[i]);
        G[Y[i]].push_back(X[i]);
        Cap[X[i]][Y[i]] = Cap[Y[i]][X[i]] = C[i];
    }

    Source = 1;
    Sink = N;
    GetFlow();
    Mark(Source, SourceBFS);
    Mark(Sink, SinkBFS);

    vector<int> Ans;
    for(int i = 1; i <= M; ++ i)
        if((SourceBFS[X[i]] && SinkBFS[Y[i]]) || (SourceBFS[Y[i]] && SinkBFS[X[i]]))
            Ans.push_back(i);

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