#include<stdio.h>
#include<algorithm>
#include<cmath>
#include<vector>
#include<queue>
#define NMax 1005
#define MMax 10005
#define INFINIT 99999999
using namespace std;

int n,m,nr,flow;
int v[NMax],father[NMax],used[2][NMax];
int X[MMax],Y[MMax];
int cost[NMax][NMax],flux[NMax][NMax];
vector<int> Graf[NMax],sol;

void Read()
{
    int x,y,z;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d%d",&x,&y,&z);
        cost[x][y]=cost[y][x]=z;
        Graf[x].push_back(y);
        Graf[y].push_back(x);
        X[i]=x; Y[i]=y;
    }
}

int BFS1()
{
    queue<int> q;
    for(q.push(1),v[1]=nr,father[1]=0;!q.empty();q.pop())
    {
        int k=q.front();
        if(k==n) continue;
        for(unsigned int i=0;i<Graf[k].size();i++)
         if(v[Graf[k][i]]!=nr && cost[k][Graf[k][i]]>flux[k][Graf[k][i]])
         {
             q.push(Graf[k][i]);
             v[Graf[k][i]]=nr;
             father[Graf[k][i]]=k;
         }
    }
    if(v[n]==nr) return 1;
    return 0;
}

void ed_karp()
{
    int Min;
    nr=1;
    while(BFS1())
    {
        for(int i=0;i<Graf[n].size();i++)
            if(v[Graf[n][i]]==nr && flux[Graf[n][i]][n]<cost[Graf[n][i]][n])
            {
                Min=INFINIT;
                father[n]=Graf[n][i];
                for(int j=n;j!=1;j=father[j])
                Min=min(Min,cost[father[j]][j]-flux[father[j]][j]);

             for(int j=n;j!=1;j=father[j])
             {
                 flux[father[j]][j]+=Min;
                 flux[j][father[j]]-=Min;
             }
             flow+=Min;
         }
         nr++;
   }
}

void BFS(int source,int ind)
{
    int k;
    queue<int> q;
    used[ind][source]=1;
    for(q.push(source);!q.empty();q.pop())
    {
        k=q.front();
        for(unsigned int i=0;i<Graf[k].size();i++)
         if(!used[ind][Graf[k][i]] && cost[k][Graf[k][i]]>abs(flux[k][Graf[k][i]]))
         {
             q.push(Graf[k][i]);
             used[ind][Graf[k][i]]=1;
         }
    }
}

void solve()
{
    int x,y;
    for(int i=1;i<=m;i++)
    {
        x=X[i]; y=Y[i];
        if((used[0][x] && used[1][y] && cost[x][y]==flux[x][y]) || (used[0][y] && used[1][x] && cost[y][x]==flux[y][x]))
          sol.push_back(i);
    }
}

void print()
{
    printf("%d\n",sol.size());
    for(unsigned int i=0;i<sol.size();i++)
     printf("%d\n",sol[i]);

}

int main()
{
    freopen("critice.in","r",stdin);
    freopen("critice.out","w",stdout);

    Read();
    ed_karp();
    BFS(1,0);
    BFS(n,1);
    solve();
    print();

    fclose(stdin);
    fclose(stdout);
    return 0;
}