#include <iostream>
#include <fstream>
#include <queue>
#include <vector>
#define NMAX 1000
#define f first
#define s second

using namespace std;

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

int n, m, cost[NMAX+10][NMAX+10], p[NMAX+10], viz[3][NMAX+10];
vector <pair <int, int> > edge;
vector <int> ans, nod[NMAX+10];
queue <int> Q;

int addFlow()
{	for(int i=1; i<=n; i++)
		p[i] = 0;
	while(!Q.empty())
		Q.pop();
	Q.push(1);
	p[1] = 1;

	while(!Q.empty())
		{	int a = Q.front();
			Q.pop();
			for(int i=0; i<nod[a].size(); i++)
				if(!p[nod[a][i]] && cost[a][nod[a][i]])
					{	p[nod[a][i]] = a;
						Q.push(nod[a][i]);
					}
		}
	return p[n];
}

void isOK(int x, int t)
{	while(!Q.empty())
		Q.pop();
	Q.push(x);
	viz[t][x] = 1;
	while(!Q.empty())
		{	int a = Q.front();
			Q.pop();
			for(int i=0; i<nod[a].size(); i++)
				if(!viz[t][nod[a][i]] && cost[a][nod[a][i]] && cost[nod[a][i]][a])
					{	viz[t][nod[a][i]] = 1;
						Q.push(nod[a][i]);
					}
		}
}

int main()
{	
	fin >> n >> m;
	for(int i=1; i<=m; i++)
		{	int nod1, nod2, c;
			fin >> nod1 >> nod2 >> c;
			nod[nod1].push_back(nod2);
			nod[nod2].push_back(nod1);
			edge.push_back({nod1, nod2});
			cost[nod1][nod2] = cost[nod2][nod1] = c;
		}
	while(addFlow())
		{	for(int i=1; i<n; i++)
				if(p[i] && cost[i][n])
					{	int newFlow = cost[i][n], curr = i;
						while(curr != 1)
							{	newFlow = min(newFlow, cost[p[curr]][curr]);
								curr = p[curr];
							}
						if(!newFlow) continue;
						cost[i][n] -= newFlow;
						cost[n][i] += newFlow;
						curr = i;
						while(curr != 1)
							{	cost[p[curr]][curr] -= newFlow;
								cost[curr][p[curr]] += newFlow;
								curr = p[curr];
							}
					}
		}
	isOK(1, 0);
	isOK(n, 1);

	for(int i=0; i<m; i++)
		{	pair <int, int> u = edge[i];
			if((viz[0][u.f] && viz[1][u.s]) || (viz[0][u.s] && viz[1][u.f]))
				ans.push_back(i + 1);
		}
	fout << ans.size() << '\n';
	for(auto u : ans)
		fout << u << '\n';
	return 0;
}