#include <iostream>
#include <fstream>
#include <queue>
#include <vector>
#define NMAX 1000
#define f first
#define s second
#define inf 2000000000

using namespace std;

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

int n, m, nod[NMAX+10][NMAX+10], viz[NMAX+10], p[NMAX+10], aux[3][NMAX+10];
vector <pair <int, int> > edge;
vector <int> ans;
queue <pair <int, int> > Q;
queue <int> Q1;

int addFlow()
{	for(int i=1; i<=n; i++)
		viz[i] = p[i] = 0;
	while(!Q.empty())
		Q.pop();
	Q.push({1, inf});
	viz[1] = 1;
	while(!Q.empty())
		{	pair <int, int> a = Q.front();
			Q.pop();
			for(int i=1; i<=n; i++)
				if(!viz[i] && nod[a.f][i])
					{	p[i] = a.f;
						viz[i] = 1;
						int newFlow = min(a.s, nod[a.f][i]);
						if(i == n)
							return newFlow;
						Q.push({i, newFlow});
					}
		}
	return 0;
}

void isOK(int x, int t)
{	while(!Q1.empty())
		Q1.pop();
	Q1.push(x);
	aux[t][x] = 1;
	while(!Q1.empty())
		{	int a = Q1.front();
			Q1.pop();
			for(int i=1; i<=n; i++)
				if(!aux[t][i] && nod[a][i] && nod[i][a])
					{	aux[t][i] = 1;
						Q1.push(i);
					}
		}
}

int main()
{	
	fin >> n >> m;
	for(int i=1; i<=m; i++)
		{	int nod1, nod2, c;
			fin >> nod1 >> nod2 >> c;
			edge.push_back({nod1, nod2});
			nod[nod1][nod2] = nod[nod2][nod1] = c;
		}
	int ok = 1;
	while(ok)
		{	ok = 0;
			int newFlow = addFlow();
			if(!newFlow) continue;
			ok = 1;
			int curr = n;
			while(curr != 1)
				{	int pr = p[curr];
					nod[pr][curr] -= newFlow;
					nod[curr][pr] += newFlow;
					curr = pr;
				}
		}
	isOK(1, 0);
	isOK(n, 1);
	for(int i=0; i<m; i++)
		{	pair <int, int> u = edge[i];
			if((aux[0][u.f] && aux[1][u.s]) || (aux[0][u.s] && aux[1][u.f]))
				ans.push_back(i + 1);
		}
	fout << ans.size() << '\n';
	for(auto u : ans)
		fout << u << '\n';
	return 0;
}