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

using namespace std;

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

const int inf= 1<<30;
const int nmax= 1000;
const int mmax= 10000;

int n, m;
vector <int> v[nmax+1];
int c[nmax+1][nmax+1], f[nmax+1][nmax+1], p[nmax+1], sol[mmax+1];
bool u[nmax+1];

struct edge {
    int x, y;
} a[mmax+1];

int bfs(  ) {
    for ( int i= 0; i<=nmax; ++i ) {
        u[i]= 0;
    }
    u[1]= 1;

    queue <int> q;
    q.push(1);
    while ( !q.empty() ) {
        int x= q.front();
        if ( x<n ) {
            for ( int i= 0; i<(int)v[x].size(); ++i ) {
                int y= v[x][i];
                if ( c[x][y]!=f[x][y] && u[y]==0 ) {
                    u[y]= 1;
                    q.push(y);
                    p[y]= x;
                }
            }
        }
        q.pop();
    }

    return u[n];
}

bool u1[nmax+1], u2[nmax+1];

void dfs ( int x, bool used[] ) {
    used[x]= 1;
    for ( int i= 0; i<(int)v[x].size(); ++i ) {
        int y= v[x][i];
        if ( f[x][y]!=c[x][y] && f[y][x]!=c[y][x] && used[y]==0 ) {
            dfs(y, used);
        }
    }
}

void maxflow(  ) {
    while ( bfs() ) {
        for ( int i= 0; i<(int)v[n].size(); ++i ) {
            int x= v[n][i];
            if ( f[x][n]!=c[x][n] && u[x]==1 ) {
                p[n]= x;
                int fmin= inf;

                for ( x= n; x!= 1; x= p[x] ) {
                    if ( c[p[x]][x]-f[p[x]][x]<fmin ) {
                        fmin= c[p[x]][x]-f[p[x]][x];
                    }
                }
                for ( x= n; x!= 1; x= p[x] ) {
                    f[p[x]][x]+= fmin;
                    f[x][p[x]]-= fmin;
                }
            }
        }
    }
}

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

    maxflow();
    dfs(1, u1), dfs(n, u2);

    int k= 0;
    for ( int i= 1; i<=m; ++i ) {
        int x= a[i].x, y= a[i].y;
        if ( ( f[x][y]==c[x][y] && u1[x]==1 && u2[y]==1 ) || ( f[y][x]==c[y][x] && u1[y]==1 && u2[x]==1 ) ) {
            ++k;
            sol[k]= i;
        }
    }

    fout<<k<<"\n";
    for ( int i= 1; i<=k; ++i ) {
        fout<<sol[i]<<"\n";
    }

    return 0;
}