#include<vector>
#include<stdio.h>
#include<queue>
using namespace std;
#define maxn 1005
#define maxm 10005
#define INF 999999
FILE *f=fopen("critice.in","r");
FILE *g=fopen("critice.out","w");
vector <int> G[maxm],viz(maxn),T(maxn),solutie;
vector <pair <int,int> > A;
queue <int> Q;
int C[maxn][maxn],F[maxn][maxn];
int verif[maxn],verif2[maxn];
int n,m,x,y,c,flow,fmin;
int bfs(){
    for(int i=1;i<viz.size();i++)
        viz[i]=0;
    viz[1]=1;
    Q.push(1);
    while(Q.empty()==0){
        int nod=Q.front();
        Q.pop();
        if(nod==n)
            continue;
        for(int i=0;i<G[nod].size();i++){
            int x=G[nod][i];
            if(C[nod][x]==F[nod][x] || viz[x])
                continue;
            Q.push(x);
            T[x]=nod;
            viz[x]=1;
        }
    }
    return viz[n];
}
void dfs1(int s){
	verif[s]=1;
	for(int i=0;i<G[s].size();i++)
		if(verif[G[s][i]]==0 && max(F[s][G[s][i]],F[G[s][i]][s])!=C[s][G[s][i]])
			dfs1(G[s][i]);
}
void dfs2(int s){
	verif2[s]=1;
	for(int i=0;i<G[s].size();i++)
		if(verif2[G[s][i]]==0 && max(F[s][G[s][i]],F[G[s][i]][s])!=C[s][G[s][i]])
			dfs2(G[s][i]);
}
void flux(){
	
    flow=0;
    for(;bfs();)
        for(int i=0;i<G[n].size();i++){
            int x=G[n][i];
            if(viz[x]==0 || F[x][n]==C[x][n])
                continue;
            T[n]=x;
            fmin=INF;
            for(int nod=n;nod!=1;nod=T[nod])
                fmin=min(fmin,C[T[nod]][nod]-F[T[nod]][nod]);
            if(fmin==0)
                continue;
            for(int nod=n;nod!=1;nod=T[nod])
            {
                F[T[nod]][nod]+=fmin;
                F[nod][T[nod]]-=fmin;
            }
            flow+=fmin;
        }
}
int main (){
    fscanf(f,"%d%d",&n,&m);
    for(int i=1;i<=m;i++){
        fscanf(f,"%d%d%d",&x,&y,&c);
        G[x].push_back(y);
        G[y].push_back(x);
        C[x][y]=c;
		C[y][x]=c;
		A.push_back(make_pair(x,y));
    }
	flux();
	dfs1(1);
	dfs2(n);
	for(int i=0;i<A.size();i++)
		if((verif[A[i].first] && verif2[A[i].second]) || (verif[A[i].second] && verif2[A[i].first]))
			solutie.push_back(i+1);
		
	fprintf(g,"%d\n",solutie.size());
	for(int i=0;i<solutie.size();i++)
		fprintf(g,"%d\n",solutie[i]);
    return 0;
}