#include <bits/stdc++.h>

using namespace std;
ifstream fin ("critice.in");
ofstream fout ("critice.out");

int n, m, maxflux;
struct much{
    int a, b, c, f;
};
much a[20005];
vector <int> v[1005];
vector <int> critice;
int last[1005], scor[40005], pereche[40005];

void bfsclav(int st){
    for(int i = 1; i <= n; i++){
        last[i] = -1;
    }
    last[st] = 0;
    queue <int> q;
    q.push(st);
    int nod;
    much nxt;
    while(!q.empty()){
        nod = q.front();
        q.pop();
        for(int i = 0; i < v[nod].size(); i++){
            nxt = a[v[nod][i]];
            if((st == n || nod != n) && last[nxt.b] == -1 && nxt.f < nxt.c){
                last[nxt.b] = v[nod][i];
                q.push(nxt.b);
            }
        }
    }
}

void fa_un_drum(){
    int nod = n, minim_ude = INT_MAX;
    while(last[nod] != 0){
        minim_ude = min(minim_ude, a[last[nod]].c - a[last[nod]].f);
        nod = a[last[nod]].a;
    }
    maxflux += minim_ude;
    nod = n;
    while(last[nod] != 0){
        a[last[nod]].f += minim_ude;
        a[pereche[last[nod]]].f -= minim_ude;
        nod = a[last[nod]].a;
    }
}

void fa_drumurile(){
    much nxt;
    for(int i = 0; i < v[n].size(); i++){
        nxt = a[v[n][i]];
        if(last[nxt.b] != -1){
            last[n] = pereche[v[n][i]];
            fa_un_drum();
        }
    }
}

void flux(){
    int lastflux = -1;
    while(lastflux != maxflux){
        lastflux = maxflux;
        bfsclav(1);
        fa_drumurile();
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    fin >> n >> m;
    for(int i = 1; i <= m; i++){
        fin >> a[i].a >> a[i].b >> a[i].c;
        v[a[i].a].push_back(i);
        pereche[i] = i + m;
        pereche[i+m] = i;
        a[i+m] = {a[i].b, a[i].a, 0, 0};
        v[a[i].b].push_back(i + m);
        a[i+2*m] = {a[i].b, a[i].a, a[i].c, 0};
        v[a[i].b].push_back(i + 2 * m);
        pereche[i+2*m] = i + 3 * m;
        pereche[i+3*m] = i + 2 * m;
        a[i+3*m] = {a[i].a, a[i].b, 0, 0};
        v[a[i].a].push_back(i + 3 * m);
    }
    flux();
    bfsclav(1);
    for(int i = 1; i <= m; i++){
        if((last[a[i].a] != -1 && last[a[i].b] == -1) || (last[a[i].a] == -1 && last[a[i].b] != -1)){
            scor[i]++;
        }
    }
    bfsclav(n);
    for(int i = 1; i <= m; i++){
        if(last[a[i].b] != -1 || last[a[i].a] != -1){
            scor[i]++;
        }
        if(scor[i] == 2){
            critice.push_back(i);
        }
    }
    fout << critice.size() << "\n";
    for(int i = 0; i < critice.size(); i++){
        fout << critice[i] << "\n";
    }
    return 0;
}