#include <fstream>
#include <string>
#include <stdio.h>
#include <vector>
#include <algorithm>
#include <math.h>
#include <set>
#include <map>
#include <string.h>
#include <queue>

using namespace std;

#ifdef DEBUG
string name = "data";
#else
string name = "critice";
#endif

ifstream fin(name + ".in");
ofstream fout(name + ".out");

#define MAXN 1001
#define MAXM 10001

struct Edge {
    int to, id;
};

int n, m;

int c[MAXN][MAXN];
int f[MAXN][MAXN];
int parent[MAXN];
vector<Edge> g[MAXN];

bool vis[MAXN];
bool critice[MAXM];

bool bfs() {
    memset(vis, 0, sizeof(vis));
    memset(parent, 0, sizeof(parent));
    
    queue<int> q;
    
    q.push(1);
    vis[1] = true;
    
    while (!q.empty()) {
        auto node = q.front();
        q.pop();
        
        if (node == n) {
            continue;
        }
        
        for (auto edge: g[node]) {
            int x = edge.to;
            if (!vis[x] && c[node][x] != f[node][x]) {
                q.push(x);
                parent[x] = node;
                vis[x] = true;
            }
        }
    }
    
    return vis[n];
}

int main() {
    
    fin >> n >> m;
    
    for (int i = 0; i < m; ++i) {
        int x,y, val;
        fin >> x >> y >> val;
        c[x][y] += val;
        c[y][x] += val;
        g[x].push_back({y, i + 1});
        g[y].push_back({x, i + 1});
    }
    
    int flow = 0;
    
    while (bfs()) {
        
        for (auto edge: g[n]) {
            
            int x = edge.to;
            
            if (!vis[x] || c[x][n] == f[x][n]) {
                continue;
            }
            
            parent[n] = x;

            int fmin = 0x3f3f3f3f;
            int node = n;
            
            while (node != 1) {
                int p = parent[node];
                
                fmin = min(fmin, c[p][node] - f[p][node]);
                
                node = p;
            }
            
            node = n;
            
            while (node != 1) {
                int p = parent[node];
                
                f[p][node] += fmin;
                f[node][p] -= fmin;
                
                node = p;
            }
            
            flow += fmin;
        }
    }
    
    queue<int> q;
    memset(vis, 0, sizeof(vis));
    
    q.push(1);
    vis[1] = true;
    
    while (!q.empty()) {
        int node = q.front();
        q.pop();
        
        for (auto edge: g[node]) {
            int x = edge.to;
            
            if (c[node][x] > 0 && f[node][x] == c[node][x]) {
                critice[edge.id] = true;
            } else if (!vis[x]) {
                q.push(x);
                vis[x] = true;
            }
        }
    }
    
    int nCritice = 0;
    
    for (int i = 1; i <= m; ++i) {
        nCritice += critice[i];
    }
    
    fout << nCritice << "\n";
    
    for (int i = 1; i <= n; ++i) {
        if (critice[i]) {
            fout << i << "\n";
        }
    }
    
    return 0;
}