#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
#define N_MAX 1002
#define M_MAX 10002
int C[N_MAX][N_MAX],F[N_MAX][N_MAX];

struct muchie
{
	int x,y;
	muchie()
	{
	}
	muchie(const int &a,const int &b)
	{
		this->x=a;
		this->y=b;
	}
};
muchie muchii[M_MAX];

int n,m,i,j;
vector <int> a[N_MAX];

bool ut[N_MAX];
int tata[N_MAX];
queue<int> Q;
int bf()
{
	memset(ut,0,sizeof(ut));
	while(!Q.empty())
		Q.pop();
	ut[1]=1;	Q.push(1);
	vector <int> ::iterator it;
	while(!Q.empty())
	{
		int nd=Q.back();
		Q.pop();
		for(it=a[nd].begin();it!=a[nd].end();it++)
		{
			if(C[nd][*it]<=F[nd][*it]||ut[*it])
				continue;
			ut[*it]=1;
			tata[*it]=nd;
			Q.push(*it);
			if(*it==n)
				return 1;
		}
	}
	if(ut[n])
		return 1;
	return 0;
}

bool A1[N_MAX],A2[N_MAX];

void df1(int nd)
{
	A1[nd]=1;
	vector <int> ::iterator it;
	for(it=a[nd].begin();it!=a[nd].end();it++)
	{
		if(!A1[*it]&&C[nd][*it]>F[nd][*it]&&C[*it][nd]>F[*it][nd])
			df1(*it);
	}
}

void df2(int nd)
{
	A2[nd]=1;
	vector <int> ::iterator it;
	for(it=a[nd].begin();it!=a[nd].end();it++)
	{
		if(!A2[*it]&&C[*it][nd]>F[*it][nd]&&C[nd][*it]>F[nd][*it])
			df2(*it);
	}
}

bool M[M_MAX];

int main()
{
	freopen("critice.in","r",stdin);
	freopen("critice.out","w",stdout);

	scanf("%d%d",&n,&m);

	for(i=1;i<=m;i++)
	{
		int x,y,z;
		scanf("%d%d%d",&x,&y,&z);
		a[x].push_back(y);
		a[y].push_back(x);
		C[x][y]=C[y][x]=z;
		muchii[i]=muchie(x,y);
	}

	while(bf())
	{
		//vector <int> ::iterator it;
		//for(it=a[n].begin();it!=a[n].end();it++)
		//{
			//tata[n]=*it;
			int MIN=(1<<30);
			int nd;
			for(nd=n;nd!=1;nd=tata[nd])
				MIN=min(MIN,C[tata[nd]][nd]-F[tata[nd]][nd]);
			for(nd=n;nd!=1;nd=tata[nd])
			{
				F[tata[nd]][nd]+=MIN;
				F[nd][tata[nd]]-=MIN;
			}
		//}
	}

	df1(1);
	df2(n);

	int nr=0;
	for(i=1;i<=m;i++)
	{
		int x,y;
		x=muchii[i].x;
		y=muchii[i].y;
		if(C[x][y]==F[x][y])
		{
			if(A1[x]==1&&A2[y]==1||A1[y]==1&&A2[x]==1)
				M[i]=1,nr++;
		}
		if(C[y][x]==F[y][x])
		{
			if(A1[x]==1&&A2[y]==1||A1[y]==1&&A2[x]==1)
				M[i]=1,nr++;
		}
	}
	printf("%d\n",nr);
	for(i=1;i<=m;i++)
		if(M[i])
			printf("%d\n",i);

	return 0;
}