#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

const int nmax = 1000;
const int mmax = 10000;

vector <int> g[nmax+1];
int e[mmax+1][2];

int r[nmax+1];
queue <int> q;
int f[nmax+1][nmax+1];

int u[nmax+1];
int dfs_mark;
void dfs( int x ) {
    u[x] = dfs_mark;
    for ( int i = 0; i < int(g[x].size()); ++ i ) {
        int xn = g[x][i];
        if ( f[x][xn] > 0 && f[xn][x] > 0 && u[xn] == 0 ) {
            dfs(xn);
        }
    }
}

int main( ) {
    int n, m;
    fin >> n >> m;
    for ( int i = 1; i <= m; ++ i ) {
        int x, y, z;
        fin >> x >> y >> z;
        g[x].push_back(y);
        g[y].push_back(x);
        f[x][y] = z;
        f[y][x] = z;
        e[i][0] = x;
        e[i][1] = y;
    }

    r[n] = -1;
    while ( r[n] != 0 ) {
        for ( int i = 1; i <= n; ++ i ) {
            r[i] = 0;
        }
        r[1] = -1;
        q.push(1);

        while ( q.empty() == 0 ) {
            int x = q.front();
            q.pop();

            for ( int i = 0; i < int(g[x].size()); ++ i ) {
                int xn = g[x][i];
                if ( f[x][xn] > 0 && r[xn] == 0 ) {
                    r[xn] = x;
                    q.push(xn);
                }
            }
        }

        if ( r[n] != 0 ) {
            for ( int i = 0; i < int(g[n].size()); ++ i ) {
                int x = g[n][i];
                int aux = f[x][n];

                while ( r[x] != -1 && aux > 0 ) {
                    if ( f[r[x]][x] < aux ) {
                        aux = f[r[x]][x];
                    }
                    x = r[x];
                }
                if ( aux > 0 ) {
                    x = g[n][i];
                    f[x][n] -= aux;
                    f[n][x] += aux;

                    while ( r[x] != -1 ) {
                        f[r[x]][x] -= aux;
                        f[x][r[x]] += aux;
                        x = r[x];
                    }
                }
            }
        }
    }

    dfs_mark = 1;
    dfs(1);
    dfs_mark = 2;
    dfs(n);

    vector <int> sol;
    for ( int i = 1; i <= m; ++ i ) {
        int x = e[i][0], y = e[i][1];
        if ( u[x]+u[y] == 3 ) {
            sol.push_back(i);
        }
    }

    fout << sol.size() << "\n";
    for ( int i = 0; i < int(sol.size()); ++ i ) {
        fout << sol[i] << "\n";
    }
    return 0;
}