#include <iostream>
#include <fstream>
#include <algorithm>
#include <queue>
#include <vector>

#define newn a[x][i]
#define ff first
#define ss second

using namespace std;

ifstream fin("critice.in");
ofstream fout("critice.out");

const int N = 1005;

typedef pair <int, int> muchie;
int n, m, t[N], c[N][N], f[N][N], rez;
bool uz1[N], uz2[N];
vector <muchie> mc(N);
vector <int> a[N], sol;
vector <bool> viz(N);
queue <int> q;

bool bfs()
{
    for(int i=1; i<=n; i++)
        viz[i] = 0;
    q.push(1); viz[1] = 1;
    while(!q.empty())
    {
        int x = q.front(); q.pop();
        for(unsigned i=0; i<a[x].size(); i++)
            if(!viz[newn] && f[x][newn] < c[x][newn])
            {
                viz[newn] = 1;
                t[newn] = x;
                q.push(newn);
            }
    }
    return viz[n];
}

void dfs(const int s, bool uz[])
{
    for(int i=1; i<=n; i++)
        viz[i] = 0;
    q.push(s); viz[s] = 1; uz[s] = 1;
    while(!q.empty())
    {
        int x = q.front(); q.pop();
        for(unsigned i=0; i<a[x].size(); i++)
            if(!viz[newn] && c[x][newn] > (f[x][newn] < 0 ? -f[x][newn] : f[x][newn]))
            {
                viz[newn] = 1;
                uz[newn] = 1;
                q.push(newn);
            }
    }
}

int main()
{
    fin>>n>>m;
    for(int i=1; i<=m; i++)
    {
        int x, y, r;
        fin>>x>>y>>r;
        a[x].push_back(y);
        a[y].push_back(x);
        c[x][y] = c[y][x] = r;
        mc[i] = muchie(x, y);
    }

    while(bfs())
    {
        for(int i=1; i<n; i++)
            if(f[i][n] < c[i][n])
            {
                int fmin = c[i][n] - f[i][n];
                for(int j=i; j!=1; j=t[j])
                    fmin = min(fmin, c[t[j]][j] - f[t[j]][j]);
                for(int j=i; j!=1; j=t[j])
                {
                    f[t[j]][j] += fmin;
                    c[j][t[j]] -= fmin;
                }
                f[i][n] += fmin;
                f[n][i] -= fmin;
                rez += fmin;
            }
    }


    dfs(1, uz1); dfs(n, uz2);

    for(int i=1; i<=n; i++)
    {
        int x = mc[i].ff, y = mc[i].ss;
        if(((uz1[x] && uz2[y]) || (uz1[y] && uz2[x])) && (c[x][y] == f[x][y] || c[y][x] == f[y][x]))
            sol.push_back(i);
    }

    fout<<sol.size()<<'\n';
    for(unsigned j=0; j<sol.size(); j++)
        fout<<sol[j]<<'\n';
    return 0;
}