#include <bits/stdc++.h>

using namespace std;

const int Nmax = 1000 + 10;
const int Mmax = 10000 + 10;
const int inf = 0x3f3f3f3f;

int n , m , i , S , D;
int dad[Nmax] , ap[2][Nmax];
int c[Nmax][Nmax] , f[Nmax][Nmax];
pair < int , int > edge[Mmax];

vector < int > v , g[Nmax];
queue < int > q;

bool bfs()
{
    bool ok = 0;

    for (q.push(S) ; !q.empty(); q.pop())
    {
        int node = q.front();
        for (auto &it : g[node])
            if (!dad[it] && c[node][it] > f[node][it])
            {
                if (it != D) dad[it] = node, q.push(it);
                else ok = 1;
            }
    }

    return ok; ///stieee
}

void dinic()
{
    S = 1; D = n;
    for (bool ok = bfs(); ok ; ok = bfs())
    {
        for (auto &it : g[D])
            if (dad[it] && c[it][D] > f[it][D])
            {
                dad[D] = it; int minn = inf;

                for (int node = D; node != S; node = dad[node])
                    minn = min(minn , c[dad[node]][node] - f[dad[node]][node]);

                if (minn <= 0) continue;

                //flow += minn;
                for (int node = D; node != S; node = dad[node])
                    f[dad[node]][node] += minn,
                    f[node][dad[node]] -= minn;
            }
        memset(dad , 0 , sizeof(dad));
    }
}

void bfs2(int start , int ind)
{
    bool ok = 0;

    ap[ind][start] = 1;
    for (q.push(start) ; !q.empty(); q.pop())
    {
        int node = q.front();
        for (auto &it : g[node])
            if (!ap[ind][it] && c[node][it] > f[node][it])
                ap[ind][it] = 1, q.push(it);
    }

    ///stieeeee
}


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

    scanf("%d %d", &n, &m);
    for (i = 1; i <= m; ++i)
    {
        int node1 , node2 , capacitate;
        scanf("%d %d %d", &node1, &node2 , &capacitate);
        edge[i] = {node1 , node2}; c[node1][node2] = c[node2][node1] = capacitate;

        g[node1].push_back(node2);
        g[node2].push_back(node1);
    }

    dinic();
    bfs2(1 , 0); bfs2(n , 1);

    for (i = 1; i <= m; ++i)
    {
        int node1 , node2;
        tie(node1 , node2) = edge[i];

        if (c[node1][node2] != f[node1][node2] && c[node1][node2] != f[node2][node1])
            continue;

        if (ap[0][node1] && ap[1][node2]) v.push_back(i);
        if (ap[1][node1] && ap[0][node2]) v.push_back(i);
    }

    printf("%d\n", v.size());
    for (auto &it : v) printf("%d\n", it);

    return 0;
}