#include <bits/stdc++.h>
using namespace std;
ifstream in("critice.in");
ofstream out("critice.out");
int viz[2][1001],lv[1001],st[1001],f[1001][1001],c[1001][1001],n;
vector<int> v[1001],sol;
queue<int> q;
pair<int,int> mu[10001];
bool bfs()
{
    int x;
    memset(lv,0,sizeof(lv));
    q.push(1);
    lv[1]=1;
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        if(x==n)
            break;
        for(auto it:v[x])
            if(!lv[it]&&f[x][it]<c[x][it])
            {
                lv[it]=lv[x]+1;
                q.push(it);
            }
    }
    while(!q.empty())
        q.pop();
    return lv[n];
}
int flow(int nr,int fl)
{
    if(nr==n)
        return fl;
    for(;st[nr]<v[nr].size();st[nr]++)
    {
        int it=v[nr][st[nr]];
        if(lv[it]==lv[nr]+1&&f[nr][it]<c[nr][it])
            if(int cf=flow(it,min(fl,c[nr][it]-f[nr][it])))
            {
                f[nr][it]+=cf;
                f[it][nr]-=cf;
                return cf;
            }
    }
    return 0;
}
void bfss(int nr,int b)
{
    q.push(nr);
    viz[b][nr]=1;
    while(!q.empty())
    {
        nr=q.front();
        q.pop();
        for(auto it:v[nr])
            if(!viz[b][it]&&f[nr][it]<c[nr][it]&&f[it][nr]<c[nr][it])
            {
                viz[b][it]=1;
                q.push(it);
            }
    }
}
int main()
{
    int m,nr1,nr2,nr,i;
    in>>n>>m;
    for(i=0;i<m;i++)
    {
        in>>nr1>>nr2>>nr;
        v[nr1].push_back(nr2);
        v[nr2].push_back(nr1);
        c[nr1][nr2]=c[nr2][nr1]=nr;
        mu[i]={nr1,nr2};
    }
    while(bfs())
    {
        memset(st,0,sizeof(st));
        while(nr1=flow(1,1<<29));
    }
    bfss(1,0);
    bfss(n,1);
    for(i=0;i<m;i++)
    {
        nr1=mu[i].first;nr2=mu[i].second;
        if((viz[0][nr1]&&viz[1][nr2])||(viz[1][nr1]&&viz[0][nr2]))
            sol.push_back(i+1);
    }
    out<<sol.size()<<"\n";
    for(auto it:sol)
        out<<it<<"\n";
    return 0;
}