#include <fstream>
#include <vector>
#include <bitset>
#include <queue>
#include <algorithm>
#include <utility>
#include <string.h>
 
#define DEBUG
 
using namespace std;
 
ifstream cin("critice.in");
ofstream cout("critice.out");
 
 
const int MAXN = 1005;
const int MAXM = 10005;
const int oo = (1<<31)-1;
 
typedef vector<int> Graph[MAXN];
typedef vector<int> :: iterator It;
 
Graph G;
bitset <MAXN> Used, Source, Sink;
queue <int> Q, Critic;
int N, M, C[MAXN][MAXN], F[MAXN][MAXN], Gather[MAXN], Father[MAXN];
pair<int, int> Vertex[MAXM];
 
inline bool BFs() {
    int Node;
    Used.reset();
    for(Q.push(1), Node = 1, Used[Node] = true ; !Q.empty() ; Q.pop(), Node = Q.front())
        for(It it = G[Node].begin(), fin = G[Node].end() ; it != fin ; ++ it)
            if(!Used[*it] && F[Node][*it] < C[Node][*it])
                Used[*it] = true, Q.push(*it), Father[*it] = Node;
    return Used[N];
}
inline void BFs(int Node, bitset<MAXN> &Use){
    for(Q.push(Node), Use[Node] = true; !Q.empty() ; Q.pop(), Node = Q.front())
        for(It it = G[Node].begin(), fin = G[Node].end(); it != fin ; ++ it)
            if(!Use[*it] && (C[Node][*it] >  (F[Node][*it] < 0 ? -F[Node][*it] : F[Node][*it])))
                Use[*it] = true, Q.push(*it);
}
int main() {
    cin >> N >> M;
    for(int i = 1 ; i <= M ; ++ i) {
        int x, y, z;
        cin >> x >> y >> z;
        G[x].push_back(y);
        G[y].push_back(x);
        C[x][y] = C[y][x] = z;
        Vertex[i] = make_pair(x, y);
    }
    for( ; BFs() ;) {
        int MinFlow = oo;
        for(int i = 1 ; i < N ; ++ i)
            if(F[i][N] < C[i][N]) {
                int MinFlow = C[i][N] - F[i][N];
                for(int j = i ; j != 1 ; j = Father[j])
                    MinFlow = min(MinFlow, C[Father[j]][j] - F[Father[j]][j]);
                for(int j = i ; j != 1 ; j = Father[j])
                    F[Father[j]][j] += MinFlow,
                    F[j][Father[j]] -= MinFlow;
                F[i][N] += MinFlow;
                F[N][i] -= MinFlow;
            }
    }
    BFs(1, Source);
    BFs(N, Sink);
    #ifndef DEBUG
    for(int i = 1 ; i <= N ; ++ i)
        cout << Source[i] << " " << Sink[i] << "\n";
    #endif
    for(int i = 1 ; i <= M ; ++ i) {
        int Node1 = Vertex[i].first, Node2 = Vertex[i].second;
        if((Source[Node1] && Sink[Node2]) || (Sink[Node1] && Source[Node2]))
            if(C[Node1][Node2] == F[Node1][Node2] || C[Node2][Node1] == F[Node2][Node1])
                Critic.push(i);
    }
    for(cout << Critic.size() <<"\n" ; !Critic.empty() ; Critic.pop())
        cout << Critic.front() << "\n";
    cin.close();
    cout.close();
    return 0;
}