#include <bits/stdc++.h>
using namespace std;
ifstream in("critice.in");
ofstream out("critice.out");
const int N = 1001;
const int M = 10001;
vector < pair < int, int > > graph[N];
queue < int > q;
int C[N][N], F[N][N], sol[N], tata[N];
bool viz[N], viz1[N], muchie[M];
int n;
bool bfs(int start)
{
    for(int i = 1; i <= n; i++)
        viz[i] = tata[i] = 0;
    viz[start] = 1;
    q.push(start);
    while(!q.empty())
    {
        int node = q.front();
        q.pop();
        for(int i = 0; i < graph[node].size(); i++)
        {
            int new_node = graph[node][i].first;
            if(viz[new_node] == 0 && F[node][new_node] < C[node][new_node])
            {
                viz[new_node] = 1;
                q.push(new_node);
                tata[new_node] = node;
            }
        }
    }
    return viz[n];
}
void bfs2(int start)
{
    viz1[start] = 1;
    q.push(start);
    while(!q.empty())
    {
        int node = q.front();
        q.pop();
        for(int i = 0; i < graph[node].size(); i++)
        {
            int new_node = graph[node][i].first;
            if(viz1[new_node] == 0 && F[new_node][node] < C[new_node][node])
            {
                viz1[new_node] = 1;
                q.push(new_node);
            }
        }
    }
}
int main()
{
    int m, i, x, y, k = 0, z;
    in>>n>>m;
    for(i = 1; i <= m; i++)
    {
        in>>x>>y>>z;
        C[x][y] = C[y][x] = z;
        graph[x].push_back({ y, i });
        graph[y].push_back({ x, i });
    }
    while(bfs(1) == 1)
    {
        for(i = 0; i < graph[n].size(); i++)
        {
            int node = graph[n][i].first;
            if(viz[node] == 0 || F[node][n] == C[node][n])
                continue;
            int Min = C[node][n] - F[node][n];
            while(node != 1)
            {
                Min = min(Min, C[tata[node]][node] - F[tata[node]][node]);
                node = tata[node];
            }
            node = graph[n][i].first;
            F[node][n] += Min;
            F[n][node] -= Min;
            while(node != 1)
            {
                F[tata[node]][node] += Min;
                F[node][tata[node]] -= Min;
                node = tata[node];
            }
        }
    }
    bfs2(n);
    for(i = 1; i <= n; i++)
    {
        for(int j = 0; j < graph[i].size(); j++)
        {
            int node = graph[i][j].first;
            int ang = graph[i][j].second;
            if(((viz[i] == 1 && viz1[node] == 1) ||(viz1[i] == 1 && viz[node] == 1)) && muchie[ang] == 0)
            {
                sol[++k] = graph[i][j].second;
                muchie[ang] = 1;
            }
        }
    }
    out<<k<<'\n';
    for(i = 1; i <= k; i++)
        out<<sol[i]<<'\n';
    return 0;

}