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

#define NMAX 10007
#define INF 10007

using namespace std;

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

void bfs(){
    int start = 0, avans = 0;
    q[avans++] = 1;
    dad[1] = -2;
    while(start < avans && dad[n] == -1){
        int Nod = q[start++];
        for(int i = 0; i < v[Nod].size() && dad[n] == -1; ++i)
            if(dad[v[Nod][i]] == -1 && Cap[Nod][v[Nod][i]] > Flux[Nod][v[Nod][i]]){
                dad[v[Nod][i]] = Nod;
                q[avans++] = v[Nod][i];
            }
    }
}

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]);
}

inline int dfs(int Nod){
    if(Nod == n)
        return 1;
    Viz[Nod] = 1;
    for(int i = 0; i < v[Nod].size(); ++ i){
        int it = v[Nod][i];
        if(Viz[it] == 0 && Flux[Nod][it] != Cap[Nod][it]){
            dad[it] = Nod;
            int ok = dfs(it);
            if(ok == 1)
                return 1;
        }
    }
    return 0;
}

inline int father(int Nod, int Min){
    if(Nod == 1)
        return Min;
    int Dad = dad[Nod];
    Min = min(Min, Cap[Dad][Nod] - Flux[Dad][Nod]);
    return father(dad[Nod], Min);
}

void father2(int Nod, int Min){
    if(Nod == 1)
        return;
    int Dad = dad[Nod];
    Flux[Nod][Dad] -= Min;
    Flux[Dad][Nod] += Min;
    father2(dad[Nod], Min);
}

void fluxmax(){
    while(dfs(1)){
        int Min = INF;
        memset(Viz, 0, sizeof(Viz));
        Min = father(n, Min);
        father2(n, Min);
    }
}

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