#include <bits/stdc++.h>
using namespace std;

const int N = 1010;
int n, m, pr[N], cap[N][N], Flux[N][N], ans, sol[N];
bool viz[N];
queue <int> Q;
vector <int> v[N];
struct edge{
    int a, b;
} M[10*N];

bool bfs(){
    while (!Q.empty()) Q.pop();
    for (int i=1; i<=n; i++) viz[i] = 0;
    Q.push(1); viz[1] = 1;
    while (!Q.empty()){
        int nod = Q.front();
        Q.pop();
        if (nod == n) continue;
        for (auto it: v[nod]){
            if (viz[it] || cap[nod][it] == Flux[nod][it]) continue;
            viz[it] = 1;
            Q.push(it);
            pr[it] = nod;
        }
    }
    return viz[n];
}

void dfs(int q, int col){
    sol[q] = col;
    for (auto it: v[q])
        if (!sol[it] && abs(Flux[q][it]) < abs(cap[q][it])) dfs(it, col);
}

int main(){
    ifstream cin ("critice.in");
    ofstream cout ("critice.out");
    cin >> n >> m;
    for (int i=1, x, y, c; i<=m; i++){
        cin >> x >> y >> c;
        cap[x][y] = cap[y][x] = c;
        v[x].push_back(y);
        v[y].push_back(x);
        M[i] = {x, y};
    }
    while (bfs()){
        for (auto it: v[n]){
            if (!viz[it] || !cap[it][n]) continue;
            pr[n] = it;
            int flow = 1e9;
            for (int nod = n; nod != 1; nod = pr[nod])
                flow = min(flow, cap[pr[nod]][nod] - Flux[pr[nod]][nod]);
            for (int nod = n; nod != 1; nod = pr[nod]){
                Flux[pr[nod]][nod] += flow;
                Flux[nod][pr[nod]] -= flow;
            }
        }
    }
    dfs(1, 1);
    dfs(n, 2);
    for (int i=1; i<=n; i++) viz[i] = 0;
    for (int i=1; i<=m; i++)
        if (sol[M[i].a] + sol[M[i].b] > 1 && sol[M[i].a] != sol[M[i].b]) ans++, viz[i] = 1;
    cout << ans << "\n";
    for (int i=1; i<=n; i++)
        if (viz[i]) cout << i << "\n";
    return 0;
}