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

#define NMAX 10007
#define INF 10000000

using namespace std;

int n, m;
vector <int> v[NMAX];
vector <int> Sol;
int dad[NMAX], Cap[NMAX][NMAX], Flux[NMAX][NMAX];
int a[NMAX], b[NMAX], c[NMAX], Viz2[NMAX], Viz1[NMAX];
queue <int> q;

void bfs(){
    while(! q.empty())
        q.pop();
    q.push(1);
    dad[1] = -1;
    while(! q.empty() && dad[n] == 0){
        int Nod = q.front();
        if(Nod == n)
            break;
        for(int i = 0; i < v[Nod].size(); ++ i)
            if(dad[v[Nod][i]] == 0 && Cap[Nod][v[Nod][i]] > Flux[Nod][v[Nod][i]]){
                q.push(v[Nod][i]);
                dad[v[Nod][i]] = Nod;
            }
        q.pop();
    }
}

void fluxmax(){
    while(1){
        memset(dad, 0, sizeof(dad));
        bfs();
        if(dad[n] == 0)
            break;
        for(int j = 0; j < v[n].size(); ++ j){
            int i = v[n][j];
            if(Cap[i][n] > Flux[i][n] && dad[i]){
                int Min = Cap[i][n] - Flux[i][n], Nod = i;
                while(Nod != 1){
                    int Dad = dad[Nod];
                    Min = min(Min, Cap[Dad][Nod] - Flux[Dad][Nod]);
                    Nod = Dad;
                }
                if(! Min)
                    continue;
                Flux[i][n] += Min;
                Flux[n][i] -= Min;
                Nod = i;
                while(Nod != 1){
                    int Dad = dad[Nod];
                    Flux[Nod][Dad] -= Min;
                    Flux[Dad][Nod] += Min;
                    Nod = Dad;
                }
            }
        }
    }
}

void dfs(int Viz[], int Nod){
    Viz[Nod] = 1;
    for(int i = 0; i < v[Nod].size(); ++ i)
        if(Viz[v[Nod][i]] == 0 && Cap[Nod][v[Nod][i]] > Flux[Nod][v[Nod][i]])
            dfs(Viz, v[Nod][i]);
}

void dfs2(int Viz[], int Nod){
    Viz[Nod] = 1;
    for(int i = 0; i < v[Nod].size(); ++ i)
        if(Viz[v[Nod][i]] == 0 && Cap[v[Nod][i]][Nod] > Flux[v[Nod][i]][Nod])
            dfs2(Viz, v[Nod][i]);
}

int main(){
    freopen("critice.in", "r", stdin);
    freopen("critice.out", "w", stdout);
    scanf("%d %d\n", &n, &m);
    for(int i = 1; i <= m; ++i){
        scanf("%d %d %d\n", &a[i], &b[i], &c[i]);
        v[a[i]].push_back(b[i]);
        v[b[i]].push_back(a[i]);
        Cap[a[i]][b[i]] = c[i];
        Cap[b[i]][a[i]] = c[i];
        Flux[a[i]][b[i]] = 0;
        Flux[b[i]][a[i]] = 0;
    }
    fluxmax();
    dfs(Viz1, 1);
    dfs2(Viz2, n);
    for(int i = 1; i <= m; ++ i){
        if(Viz1[a[i]] == 1 && Viz2[b[i]] == 1 && Flux[a[i]][b[i]] == c[i])
            Sol.push_back(i);
        else
        if(Viz1[b[i]] == 1 && Viz2[a[i]] == 1 && Flux[b[i]][a[i]] == c[i])
            Sol.push_back(i);
    }
    printf("%d\n", Sol.size());
    for(int i = 0; i < Sol.size(); ++i)
        printf("%d\n", Sol[i]);
    return 0;
}