#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <cstring>
using namespace std;
ifstream fin("critice.in");
ofstream fout("critice.out");
#define MAX 1009
#define cout fout
bool viz[MAX];
int C[MAX][MAX], dad[MAX], n, F[MAX][MAX];
const int INF = (1<<30);
vector <int> G[MAX];
typedef vector <int> :: iterator iter;

pair <int, int> q[MAX * 10];
int st[10 * MAX], a[MAX], b[MAX];
int bfs()
{
    queue <int> Q;
    memset(viz, false, sizeof(viz));
    Q.push(1);
    viz[1] = 1;
    while(Q.size())
    {
        int nod = Q.front();
        Q.pop();
        for(iter it = G[nod].begin(); it != G[nod].end() ; it++)
            if(!viz[*it] && C[nod][*it] > F[nod][*it])
            {
                dad[*it] = nod;
                viz[*it] = 1;
                if(*it == n)
                    continue;
                Q.push(*it);
            }
    }
    return viz[n];
}

void bf(int t, int viz[])
{
    queue <int> Q;
    int i;
    for(i = 1 ; i <= n ; i++)
    {
        viz[i] = 0;
        dad[i] = 0;
    }
    Q.push(t);
    viz[t] = 1;
    while(Q.size())
    {
        int nod = Q.front();
        Q.pop();
        for(iter it = G[nod].begin(); it != G[nod].end() ; it++)
            if(!viz[*it] && C[nod][*it] > F[nod][*it] && C[*it][nod] > F[*it][nod])
            {
                dad[*it] = nod;
                viz[*it] = 1;
                Q.push(*it);
            }
    }
}

int main()
{
    int m, x, y, z, minim, i, flow = 0, dr = 0;
    fin >> n >> m;
    for(i = 1 ; i <= m ; i ++)
    {
        fin >> x >> y >> z;
        q[i] = make_pair(x, y);
        C[x][y] = z;
        C[y][x] = z;
        G[x].push_back(y);
        G[y].push_back(x);
    }

    while(bfs())
        for(iter it = G[n].begin() ; it != G[n].end() ; it ++)
            if(viz[*it] && C[*it][n] != F[*it][n])
            {
                dad[n] = *it;
                minim = INF;
                for(i = n ; dad[i] ; i = dad[i])
                    minim = min(minim, C[dad[i]][i] - F[dad[i]][i]);
                if(minim > 0)
                {
                    for(i = n ; dad[i] ; i = dad[i])
                    {
                        F[dad[i]][i] += minim;
                        F[i][dad[i]] -= minim;
                    }
                    flow += minim;
                }
            }
    bf(1, a);
    bf(n, b);
    for(i = 1 ; i <= m ; i++)
    {
        x = q[i].first;
        y = q[i].second;
        if((a[x] && b[y]) || (a[y] && b[x]))
            st[++dr] = i;
    }
    cout << dr << "\n";
    for(i = 1 ; i <= dr ; i ++)
        cout << st[i] << "\n";
}