#include <bits/stdc++.h>

using namespace std;

ifstream fin("critice.in");
ofstream fout("critice.out");

#define cin fin 
#define cout fout

struct pair_hash {
    size_t operator()(const pair<int,int>& p) const noexcept {
        return ((size_t)p.first << 32) ^ (size_t)p.second;
    }
};

unordered_map<pair<int, int>, int, pair_hash> point;
unordered_map<pair<int, int>, int, pair_hash> mm;
vector<int> g[1001];
int c[1001][1001];
int flow[1001][1001];
int parent[1001];
int n, m;
bool v[1001];

bool bfs() {
    queue<int> q;
    q.push(1);
    memset(v,0,sizeof(v));
    v[1]=true;
    while(!q.empty()) {
        int node = q.front();
        q.pop();
        if (node==n) continue;
        for(auto i : g[node]) {
            if (flow[node][i]==c[node][i] || v[i]) continue;
            v[i]=true;
            q.push(i);
            parent[i]=node;
        }
    }
    return v[n];
}

int main()
{
    cin >> n >> m;
    int x, y, cap;
    for(int i = 1; i <= m; i++) {
        cin >> x >> y >> cap;
        c[x][y]+=cap;
        g[x].push_back(y);
        g[y].push_back(x);
        mm[{x, y}] = c[x][y];
        mm[{y, x}] = c[y][x];
        point[{x, y}] = i;
        point[{y, x}] = i;
    }
    int ans=0;
    int av[1001];
    for(ans = 0; bfs(); ) {
        for(auto node : g[n]) {
            if (flow[node][n]==c[node][n] || !v[node]) continue;
            parent[n]=node;
            int flowmin=INT_MAX;
            for(node=n; node != 1; node=parent[node]) {
                flowmin = min(flowmin, c[parent[node]][node]-flow[parent[node]][node]);
            }
            if (flowmin==0) continue;
            for(node=n; node != 1; node=parent[node]) {
                if (mm[{parent[node], node}]>0) { 
                    mm[{parent[node], node}]--;
                    c[parent[node]][node]--;
                } else {
                    av[++ans] = point[{parent[node], node}];
                }
                flow[parent[node]][node] += flowmin;
                flow[node][parent[node]] -= flowmin;
            }
        }
    }
    cout << ans << "\n";
    sort(av+1,av+1+ans);
    for(int i = 1; i <=ans; i++) {
        cout << av[i] << "\n";
    }
    return 0;
}