// http://infoarena.ro/problema/critice
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

#define maxSize 1001
#define INFINITY 0x3f3f3f3f
#define source 1

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

int destination,edges;
bool visit[maxSize];
int father[maxSize];
int capacity[maxSize][maxSize];
int currentFlow[maxSize][maxSize];
int currentFlow2[maxSize][maxSize];
vector<int> graph[maxSize];
vector< pair<int,int> > edge;
vector<int> critical;

bool breadthFirst();
bool breadthFirst2();
int maxFlow();
int maxFlow2();

int main() {
	in >> destination >> edges;

	int from,to,flow;
	for(int i=1;i<=edges;i++) {
		in >> from >> to >> flow;
		capacity[from][to] = flow;
		capacity[to][from] = flow;

		edge.push_back(make_pair(from,to));

		graph[from].push_back(to);
		graph[to].push_back(from);
	}

	int initialFlow = maxFlow();

	vector< pair<int,int> >::iterator it,end;
	end = edge.end();

	for(it=edge.begin();it!=end;++it) 
		if(capacity[it->first][it->second] == abs(currentFlow[it->first][it->second])) {
			capacity[it->first][it->second] += 100000;
			capacity[it->second][it->first] += 100000;

			int newFlow = maxFlow2();
			if(newFlow > initialFlow)
				critical.push_back(it - edge.begin() + 1);

			capacity[it->first][it->second] -= 100000;
			capacity[it->second][it->first] -= 100000;
		}

	out << critical.size() << "\n";

	vector<int>::iterator sit,send;
	send = critical.end();
	for(sit=critical.begin();sit!=send;++sit)
		out << *sit << "\n";

	in.close();
	out.close();

	return (0);
}

bool breadthFirst() {
	memset(visit,false,sizeof(visit));
	visit[source] = true;

	int node;
	vector<int>::iterator it,end;

	queue<int> myQueue;
	myQueue.push(source);

	while(!myQueue.empty()) {
		node = myQueue.front();
		myQueue.pop();

		if(node == destination)
			continue;

		end = graph[node].end();
		for(it=graph[node].begin();it!=end;++it)
			if(!visit[*it] && currentFlow[node][*it] < capacity[node][*it]) {
				visit[*it] = true;
				myQueue.push(*it);
				father[*it] = node;
			}
	}

	return visit[destination];
}

bool breadthFirst2() {
	memset(visit,false,sizeof(visit));
	visit[source] = true;

	int node;
	vector<int>::iterator it,end;

	queue<int> myQueue;
	myQueue.push(source);

	while(!myQueue.empty()) {
		node = myQueue.front();
		myQueue.pop();

		if(node == destination)
			continue;

		end = graph[node].end();
		for(it=graph[node].begin();it!=end;++it)
			if(!visit[*it] && currentFlow2[node][*it] < capacity[node][*it]) {
				visit[*it] = true;
				myQueue.push(*it);
				father[*it] = node;
			}
	}

	return visit[destination];
}

int maxFlow() {
	int maxFlow = 0;
	vector<int>::iterator it,end;

	for(int i=1;i<=destination;i++)
		memset(currentFlow[i],0,sizeof(currentFlow[i]));

	while(breadthFirst()) {
		end = graph[destination].end();

		for(it=graph[destination].begin();it!=end;++it)
			if(visit[*it] && capacity[*it][destination] != currentFlow[*it][destination]) {
				int minFlow = INFINITY;

				father[destination] = *it;

				for(int node=destination;node!=source;node=father[node])
					minFlow = min(minFlow,capacity[father[node]][node] - currentFlow[father[node]][node]);

				if(minFlow) {
					for(int node=destination;node!=source;node=father[node]) {
						currentFlow[father[node]][node] += minFlow;
						currentFlow[node][father[node]] -= minFlow;
					}

					maxFlow += minFlow;
				}
			}
	}

	return maxFlow;
}

int maxFlow2() {
	int maxFlow = 0;
	vector<int>::iterator it,end;

	for(int i=1;i<=destination;i++)
		memset(currentFlow2[i],0,sizeof(currentFlow2[i]));

	while(breadthFirst2()) {
		end = graph[destination].end();

		for(it=graph[destination].begin();it!=end;++it)
			if(visit[*it] && capacity[*it][destination] != currentFlow2[*it][destination]) {
				int minFlow = INFINITY;

				father[destination] = *it;

				for(int node=destination;node!=source;node=father[node])
					minFlow = min(minFlow,capacity[father[node]][node] - currentFlow2[father[node]][node]);

				if(minFlow) {
					for(int node=destination;node!=source;node=father[node]) {
						currentFlow2[father[node]][node] += minFlow;
						currentFlow2[node][father[node]] -= minFlow;
					}

					maxFlow += minFlow;
				}
			}
	}

	return maxFlow;
}