#include <fstream>
#include <vector>
#include <algorithm>
#include <limits>
#include <queue>
#include <set>
#define mp make_pair
#define pb push_back
#define INF numeric_limits<int>::max()
#define int64 long long
using namespace std;
ifstream in("critice.in");
ofstream out("critice.out");
vector< vector<int> > a;
queue<int> q;
set<int> sol;
int flow[1005][1005],n,k,s,d,maxflow,pre[1005],f[1005],v1[1005],v2[1005];
vector< pair<int,int> > mc;
//bfs
void bfs(int start)
{
    for(int i=1;i<=n;i++)pre[i]=0;
    k=0;
    pre[s]=s;
    q.push(start);
    while(!q.empty())
    {
        int x=q.front();q.pop();
        for(auto i: a[x])
        if(pre[i]==0 && flow[x][i]>0)
        {
            if(i==d)
            {
                f[++k]=x;
                continue;
            }
            pre[i]=x;
            q.push(i);
        }
    }
}
void bf(int start,int v[])
{
    v[start]=1;
    q.push(start);
    while(!q.empty())
    {
        int x=q.front();q.pop();
        for(auto i: a[x])
        if(flow[x][i] && v[i]==0)
        {
            v[i]=1;
            q.push(i);
        }
    }
}
int main()
{
    int m;
    in>>n>>m;
    a=vector< vector<int> > (n+1);
    for(int i=1;i<=m;i++)
    {
        int x,y,z;
        in>>x>>y>>z;
        a[x].pb(y);
        a[y].pb(x);
        flow[x][y]=flow[y][x]=z;
        mc.pb({x,y});
    }
    for(s=1,d=n;;)//sursa, destinatie
    {
        bfs(s);
        if(k==0)break;
        for(int i=1;i<=k;i++)
        {
            int mx=INF;
            pre[d]=f[i];

            for(int x=d;pre[x]!=x;x=pre[x])
            mx=min(mx,flow[pre[x]][x]);

            for(int x=d;pre[x]!=x;x=pre[x])
            {
                flow[pre[x]][x]-=mx;
                flow[x][pre[x]]+=mx;
            }

            maxflow+=mx;
        }
    }
    bf(s,v1);
    bf(d,v2);
    for(unsigned i=0;i<m;i++)
        if((v1[mc[i].first] && v2[mc[i].second]) || (v2[mc[i].first] && v1[mc[i].second]) && flow[mc[i].first][mc[i].second]==0)
        sol.insert(i+1);
    out<<sol.size()<<'\n';
    for(auto i: sol)
        out<<i<<'\n';
    return 0;
}