#include <bits/stdc++.h>

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

const int NMAX = 1000;

struct Edge {
    int to, cap, flow, rev;
};

struct Data {
    int x, y;
}muc[1 + NMAX * 10];

vector<Edge> g[1 + NMAX];
int dist[1 + NMAX], src, dest, n, cap[1 + NMAX][1 + NMAX], rem[1 + NMAX], flow[1 + NMAX][1 + NMAX];

void addEdge(int i, int j) {
    Edge a = {j, cap[i][j], 0, g[j].size()};
    Edge b = {i, cap[j][i], 0, g[i].size()};
    g[i].push_back(a);
    g[j].push_back(b);
}

bool bfs() {
    for(int i = 1; i <= n; i ++)
        dist[i] = -1;

    queue<int> q;
    dist[src] = 0;
    q.push(src);

    while(q.size()) {
        int from = q.front();
        q.pop();
        for(auto it : g[from]) {
            if(dist[it.to] == -1 && it.flow < it.cap) {
                dist[it.to] = 1 + dist[from];
                q.push(it.to);
            }
        }
    }

    return (dist[dest] >= 0);
}

int dfs(int from, int deltaflow) {
    if(from == dest)
        return deltaflow;
    for(int i = rem[from]; i < g[from].size(); i ++) {
        Edge &e = g[from][i];
        if(dist[e.to] == dist[from] + 1 && e.flow < e.cap) {
            int addflow = dfs(e.to, min(deltaflow, e.cap - e.flow));
            if(addflow > 0) {
                Edge &rev = g[e.to][e.rev];
                e.flow += addflow;
                flow[from][e.to] += addflow;
                rev.flow -= addflow;
                flow[e.to][from] -= addflow;
                return addflow;
            }
        }
    }
    return 0;
}

int dinic() {
    int maxflow = 0;
    while(bfs()) {
       for(int i = 1; i <= n; i ++)
            rem[i] = 0;
        int aux = dfs(src, INT_MAX);
        while(aux) {
            maxflow += aux;
            aux = dfs(src, INT_MAX);
        }
    }

    return maxflow;
}

bool visited[1 + NMAX];
vector<Data> sol;
int mark[1 + NMAX]; /// mark[node] = 0 -> nu se poate ajunge nicaieri din node, mark[node] = 1/ n se poate ajunge in 1 sau n, mark[node] = n + 1 se poate ajunge in 1 si n

void computemark(int node, int x) {
    visited[node] = 1;
    mark[node] += x;
    for(auto it : g[node])
        if(!visited[it.to] && it.flow < it.cap)
            computemark(it.to, x);
}

int main() {
    int m;
    in >> n >> m;
    src = 1;
    dest = n;
    for(int i = 1; i <= m; i ++) {
        int x, y, z;
        in >> x >> y >> z;
        cap[x][y] = cap[y][x] = z;
        addEdge(x, y);
        muc[i].x = x;
        muc[i].y = y;
    }
    int maxflow = dinic();

    computemark(src, src);
    for(int i = 1; i <= n; i ++)
        visited[i] = 0;
    computemark(dest, dest);

    vector<int> sol;
    for(int i = 1; i <= m; i ++) {
        int x = muc[i].x, y = muc[i].y;
        if(flow[x][y] == cap[x][y] || flow[y][x] == cap[y][x]) {
            if((mark[x] == src || mark[x] == src + dest) && (mark[y] == dest || mark[y] == src + dest))
                sol.push_back(i);
            else if((mark[x] == dest || mark[x] == src + dest) && (mark[y] == src || mark[y] == src + dest))
                sol.push_back(i);
        }
    }
    out << sol.size() << "\n";
    for(auto it : sol)
        out << it << "\n";

    return 0;
}