#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>
#include <bitset>

#define v first
#define e second
#define Nmax 1005
#define INF 0x3f3f3f3f

using namespace std;

class edge{
public:
    int x,y,capacity,flow,ind;
    edge(){
        x = y = capacity = flow = ind = 0;
    }
    edge(int a,int b,int c,int f,int ii){
        this->x = a;
        this->y = b;
        this->capacity = c;
        this->flow = f;
        this->ind = ii;
    }
};
bitset<Nmax> used;
vector<pair<int,int> > G[Nmax];
vector<edge> E;
vector<int> sol;
queue<int> Q;
int nre = -1,N,M;
int daddy[Nmax];
int colorat[Nmax];

void Insert(int a,int b,int c,int f,int ii)
{
    ++nre;
    E.push_back(edge(a,b,c,f,ii));
    G[a].push_back(make_pair(b,nre));
}

void Read()
{
    scanf("%d%d",&N,&M);
    int a,b,c;
    for(int i = 1; i <= M; ++i)
    {
        scanf("%d%d%d",&a,&b,&c);
        Insert(a,b,c,0,i);
        Insert(b,a,c,0,i);
    }
}

bool BFS(int k)
{
    used = 0;
    used[k] = 1;
    Q.push(k);
    while(!Q.empty())
    {
        k = Q.front(); Q.pop();
        if(k == N)continue;
        for(vector<pair<int,int> >::iterator it = G[k].begin(); it != G[k].end(); ++it)
            if(!used[it->v] && E[it->e].capacity - E[it->e].flow != 0)
            {
                used[it->v] = 1;
                daddy[it->v] = it->e;
                Q.push(it->v);
            }
    }
    return used[N];
}

void FLOW(int k)
{
    int minFLOW,maxFLOW = 0;
    while(BFS(k))
    for(vector<pair<int,int> >::iterator it = G[N].begin(); it != G[N].end(); ++it)
    {
        if(E[it->e^1].capacity == E[it->e^1].flow)
            continue;
        minFLOW = INF;
        daddy[N] = it->e^1;
        for(int nodc = N; nodc != 1; nodc = E[daddy[nodc]].x)
            minFLOW = min(minFLOW,E[daddy[nodc]].capacity - E[daddy[nodc]].flow);
        if(minFLOW == 0)
            continue;
        for(int nodc = N; nodc != 1; nodc = E[daddy[nodc]].x)
        {
            E[daddy[nodc]].flow += minFLOW;
            E[daddy[nodc]^1].flow -= minFLOW;
        }
        maxFLOW += minFLOW;
    }
    ///printf("%d\n",maxFLOW);
}

void cauta(int k,int cul)
{
    Q.push(k);
    used = 0;
    used[k] = 1;
    colorat[k] = cul;

    while(!Q.empty())
    {
        k = Q.front(); Q.pop();
        for(vector<pair<int,int> >::iterator it = G[k].begin(); it != G[k].end(); ++it)
        {
            int w = it->e;
            if(!used[it->v] && E[it->e^1].capacity - E[it->e^1].flow != 0 && E[it->e^1].flow >= 0)
            {
                Q.push(it->v);
                used[it->v] = 1;
                colorat[it->v] = cul;
            }
        }
    }
}

void print()
{
    for(int i = 0; i <= nre; i+=2)
        if(colorat[E[i].x] + colorat[E[i].y] == 3)
            sol.push_back(E[i].ind);
    printf("%d\n",sol.size());
    for(int i = 0; i < (int)sol.size(); ++i)
        printf("%d\n",sol[i]);
}

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

    Read();
    FLOW(1);
    cauta(1,1);
    cauta(N,2);
    print();

    return 0;
}