#include<fstream>
#include<vector>
#include<cstring>
#include<queue>
using namespace std;
ifstream f("critice.in");
ofstream g("critice.out");
int n,m,i,x,y,flux,mini,c[1010][1010],fl[1010][1010],t[1010];
queue<int>q;
vector<int>sol,l[1010];
bool viz[1010],a[1010],b[1010];
struct ooo{int x,y,c;};
ooo v[10100];
inline int abs(int x)
{
    if(x<0)
    return -x;
    return x;
}
void bfs1(int x,bool a[])
{
    int i,y;
    q.push(x);
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        for(i=0;i<l[x].size();++i)
        {
            y=l[x][i];
            if(abs(fl[x][y])<c[x][y]&&!a[y]&&y!=n&&y!=1)
            {
                a[y]=1;
                q.push(y);
            }
        }
    }
}
int bfs()
{
    int i,x,y;
    memset(viz,0,sizeof(viz));
    q.push(1);
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        for(i=0;i<l[x].size();++i)
        {
            y=l[x][i];
            if(fl[x][y]<c[x][y]&&!viz[y])
            {
                viz[y]=1;
                q.push(y);
                t[y]=x;
            }
        }
    }
    return viz[n];
}
int main()
{
    f>>n>>m;
    for(i=1;i<=m;++i)
    {
        f>>v[i].x>>v[i].y>>v[i].c;
        l[v[i].x].push_back(v[i].y);
        l[v[i].y].push_back(v[i].x);
        c[v[i].x][v[i].y]=c[v[i].y][v[i].x]=v[i].c;
    }
    while(bfs())
    {
        for(i=1;i<=n;++i)
        {
            if(c[i][n]>fl[i][n])
            {
                mini=c[i][n]-fl[i][n];
                x=i;
                while(x!=1)
                {
                    mini=min(mini,c[t[x]][x]-fl[t[x]][x]);
                    x=t[x];
                }
                x=i;
                while(x!=1)
                {
                    fl[t[x]][x]+=mini;
                    fl[x][t[x]]-=mini;
                    x=t[x];
                }
                fl[i][n]+=mini;
                fl[n][i]-=mini;
                flux+=mini;
            }
        }
    }
    bfs1(1,a);
    bfs1(n,b);
    a[1]=b[n]=1;
    for(i=1;i<=m;++i)
    {
        x=v[i].x;
        y=v[i].y;
        if(((a[x]&&b[y])||(a[y]&&b[x]))&&(c[x][y]==fl[x][y]||c[y][x]==fl[y][x]))
        sol.push_back(i);
    }
    g<<sol.size()<<'\n';
    for(i=0;i<sol.size();++i)
    g<<sol[i]<<'\n';
    return 0;
}