#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
ofstream fout ("critice.out" );
ifstream fin ("critice.in" );
pair < pair < int , int > , int > muc[10005];
vector < int > w[1005],ans;
int n,m,i,S,D,a,b,nod,aux,ok,mini;
int flux[1005][1005],cap[1005][1005],parent[1005],vizS[1005],vizD[1005];
inline void bfs()
{
    queue < int > q;
    q.push( S );
    memset( parent , 0 , sizeof( parent ) );
    parent[ S ] = -1;
    while( q.size() )
    {
        aux = q.front();
        q.pop();
        for( auto it : w[ aux ] )
        {
            if( cap[ aux ][ it ] == flux[ aux ][ it ] )
                continue;
            if( parent[ it ] == 0 && it != D )
            {
                parent[ it ] = aux;
                q.push( it );
            }
            else if( it == D )
                ok = 1;
        }
    }
}
inline void dinitz()
{
    do
    {
        ok = 0;
        bfs();
        for( auto it : w[ D ] )
        {
            mini = 1e9;
            if( cap[ it ][ D ] != flux[ it ][ D ] && parent[ it ] )
                parent[ D ] = it;
            else
                continue;
            for( nod = D ; nod != S ; nod = parent[ nod ] )
                mini = min( mini , cap[ parent[ nod ] ][ nod ] - flux[ parent[ nod ] ][ nod ] );
            for( nod = D ; nod != S ; nod = parent[ nod ] )
            {
                flux[ parent[ nod ] ][ nod ] += mini;
                flux[ nod ][ parent[ nod ] ] += mini;
            }
        }
    }while( ok );
}
void DFSS( int nod )
{
    vizS[ nod ] = 1;
    for( auto it : w[ nod ] )
        if( cap[ nod ][ it ] != flux[ nod ][ it ] && vizS[ it ] == 0 )
            DFSS( it );
}
void DFSD( int nod )
{
    vizD[ nod ] = 1;
    for( auto it : w[ nod ] )
        if( cap[ nod ][ it ] != flux[ nod ][ it ] && vizD[ it ] == 0 )
            DFSD( it );
}
int main()
{
    fin>>n>>m;
    for( i = 1 ; i <= m ; i++ )
    {
        fin>>muc[ i ].x.x>>muc[ i ].x.y>>muc[ i ].y;
        w[ muc[ i ].x.x ].push_back( muc[ i ].x.y );
        w[ muc[ i ].x.y ].push_back( muc[ i ].x.x );
        cap[ muc[ i ].x.x ][ muc[ i ].x.y ] = muc[ i ].y;
        cap[ muc[ i ].x.y ][ muc[ i ].x.x ] = muc[ i ].y;
    }
    S = 1;
    D = n;
    dinitz();
    DFSS( S );
    DFSD( D );
    for( i = 1 ; i <= m ; i++ )
    {
        a = muc[ i ].x.x;
        b = muc[ i ].x.y;
        if( flux[ a ][ b ] == cap[ a ][ b ] && ( vizS[ a ] && vizD[ b ] ) )
            ans.push_back( i );
    }
    fout<<ans.size()<<'\n';
    for( auto it : ans )
        fout<<it<<'\n';
    return 0;
}