#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define pf push_front
#define nmax 100005
#define inf 1000000000
using namespace std;
ifstream f("critice.in");
ofstream g("critice.out");
int n,m;
vector<int> adj[1005];
int cap[1005][1005],tata[1005],flow;
bool viz1[1005],viz2[1005];
pair<int,int> edge[10005];
bool bfs(int node)
{
    vector<bool> viz(n+5,0);
    viz[1]=1;
    queue<int> q;
    q.push(1);
    while(!q.empty())
    {
        int crt=q.front();
        q.pop();
        for(auto x:adj[crt])
        {
            if(viz[x]==0&&cap[crt][x]>0)
            {
                viz[x]=1;
               // if(x==n) return 1;
                q.push(x);
                tata[x]=crt;
                if(x==n) return 1;
            }
        }
    }
    return 0;
}
void dfs1(int node)
{
    viz1[node]=1;
    for(auto x:adj[node])
    {
        if(cap[node][x]>0&&viz1[x]==0)
        {
            viz1[x]=1;
            dfs1(x);
        }
    }
}
void dfs2(int node)
{
    viz2[node]=1;
    for(auto x:adj[node])
    {
        if(cap[node][x]>0&&viz2[x]==0)
        {
            viz2[x]=1;
            dfs2(x);
        }
    }
}
int flux(int node,int flw)
{
    while(node!=1)
    {
        flw=min(flw,cap[tata[node]][node]);
        node=tata[node];
    }
    node=n;
    while(node!=1)
    {
        cap[tata[node]][node]-=flw;
        cap[node][tata[node]]+=flw;
        node=tata[node];
    }
    return flw;
}
int main()
{
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y,c;
        f>>x>>y>>c;
        cap[x][y]=c;
        adj[x].pb(y);
        adj[y].pb(x);
        edge[i]={x,y};
        cap[y][x]=c;


    }
    while(bfs(1))
    {
        flow+=flux(n,1e9);
    }
    dfs1(1);
    dfs2(n);
    vector<int> sol;
    for(int i=1;i<=m;i++)
    {
        int x=edge[i].first,y=edge[i].second;
        if(viz1[x]==1&&viz2[y]==1&&cap[x][y]==0)
        {
            sol.pb(i);
        }
        else
        {
            if(viz1[y]==1&&viz2[x]==1&&cap[y][x]==0)
            {
                sol.pb(i);
            }
        }
    }
    g<<sol.size()<<'\n';
    for(int i=0;i<sol.size();i++) g<<sol[i]<<'\n';


}