#include <bits/stdc++.h>

using namespace std;

ifstream in ("critice.in");
ofstream out("critice.out");

const int nmax = 1e3, mmax = 1e4;

int n, m, source, sink;

int rez[nmax + 2][nmax + 2];

vector <int> muchii[nmax + 2];

int lay[nmax + 2];

int ptrM[nmax + 2];

bool bfs(){
    fill(lay + 1, lay + n + 1, -1);
    queue <int> q;
    lay[source] = 0;
    q.push(source);
    while(!q.empty()){
        int elem = q.front(); q.pop();
        for(auto & x:muchii[elem])
            if(lay[x] == -1 && rez[elem][x] != 0){
                lay[x] = lay[elem] + 1;
                q.push(x);
            }
    }
    return (lay[sink] != -1);
}

int dfs(int nod, int f){
    if(nod == sink)
        return f;
    for(;ptrM[nod] < muchii[nod].size(); ptrM[nod]++){
        int x = muchii[nod][ptrM[nod]];
        if(lay[nod] == lay[x] - 1 && rez[nod][x] != 0){
            int ret = dfs(x, min(f, rez[nod][x]));
            if(ret == -1)
                continue;
            rez[nod][x] -= ret;
            rez[x][nod] += ret;
            return ret;
        }
    }
    return -1;
}

vector <pair<int, int> > mch;

bool mrk1[nmax + 2], mrk2[nmax + 2];

void bfs1(){
    queue <int> q;
    mrk1[source] = true;
    q.push(source);
    while(!q.empty()){
        int elem = q.front(); q.pop();
        for(auto & x:muchii[elem])
            if(mrk1[x] == false && rez[elem][x] != 0){
                mrk1[x] = true;
                q.push(x);
            }
    }
}

void bfs2(){
    queue <int> q;
    mrk2[sink] = true;
    q.push(sink);
    while(!q.empty()){
        int elem = q.front(); q.pop();
        for(auto & x:muchii[elem])
            if(mrk2[x] == false && rez[x][elem] != 0){
                mrk2[x] = true;
                q.push(x);
            }
    }
}

int main()
{
    in >> n >> m;
    source = 1, sink = n;
    for(int i = 1; i <= m; i++){
        int x, y, c;
        in >> x >> y >> c;
        mch.push_back({x, y});
        rez[x][y] = c;
        rez[y][x] = c;
        muchii[x].push_back(y);
        muchii[y].push_back(x);
    }

    while(bfs()){
        fill(ptrM + 1, ptrM + n + 1, 0);
        while(dfs(source, 1000000) != -1);
    }
    bfs1();
    bfs2();
    vector <int> ans;
    for(int i = 0; i < mch.size(); i++){
        pair<int, int> & x = mch[i];
        if( (mrk1[x.first] == true && mrk2[x.second] == true) || (mrk2[x.first] == true && mrk1[x.second] == true) )
            ans.push_back(i + 1);
    }
    out << ans.size() << "\n";
    for(auto & x:ans)
        out << x << "\n";
    return 0;
}