#include<stdio.h>

typedef struct nod { int x,c; nod *d; } nod;

typedef struct list { int x; list *s,*d;} list;

nod *v[1010],*a[1010];

list *l;



int n,m,h[1010],f[1010][1010],c[1010][1010],lx[10100],ly[10100],s[1010];

long e[1010],flux;



void add(int x,int y,int c)

{

  nod *p;

  p=new nod;

  p->x=y;

  p->c=c;

  p->d=v[x];

  v[x]=p;

}



void READ(){

FILE *f;

int i,x,y,C;



   f=fopen("critice.in","r");

   fscanf(f,"%d %d",&n,&m);



   for(i=1;i<=m;i++){

	fscanf(f,"%d %d %d",&x,&y,&C);

	c[x][y]=c[y][x]=C;

	lx[i]=x;

	ly[i]=y;

	add(x,y,i);

	add(y,x,i);

   }

   fclose(f);

}



void INIT(){

int i,j;



   for(i=1;i<=n;i++){

	h[i]=e[i]=0;

   }

   h[1]=n;



   for(i=1;i<=n;i++)

      for(j=1;j<=n;j++)

	 f[i][j]=0;





   nod *p;

   p=v[1];

   while(p){

     f[1][p->x]=c[1][p->x];

     f[p->x][1]=-f[1][p->x];

     e[p->x]=f[1][p->x];

     p=p->d;

   }



   list *ll;

   if(!l)

      for(i=n-1;i>1;i--){

	 ll=new list;

	 ll->d=l;

	 ll->s=0;

	 if(l) l->s=ll;

	 ll->x=i;

	 l=ll;

      }



   for(i=1;i<=n;i++)

      a[i]=v[i];

}





void RIDICA(int x){

nod *p;

int min=2*n;



  p=v[x];

  while(p){

     if(h[p->x]>=h[x] && h[p->x]+1<min) min=h[p->x]+1;

     p=p->d;

  }

h[x]=min;

}





void POMPEAZA(int x,int y){

int min;

min=(e[x]<c[x][y]-f[x][y]?e[x]:c[x][y]-f[x][y]);

f[x][y]+=min;

f[y][x]=-f[x][y];

e[x]-=min;

e[y]+=min;

}



void DESCARCA(int x){

int y;

  while(e[x])

     if(!a[x]) {

	a[x]=v[x];

	RIDICA(x);

     }

     else {

	y=a[x]->x;

	if(h[x]==h[y]+1 && c[x][y]-f[x][y]>0) POMPEAZA(x,y);

	else a[x]=a[x]->d;

     }

}





void FLUX(){

int x,hh;

list *L;



  L=l;



  while(L){

     x=L->x;

     hh=h[x];



     DESCARCA(x);

     if(hh<h[x]) { if(L->s) {

		       (L->s)->d=L->d;

		       if(L->d) (L->d)->s=L->s;

		       L->s=0;

		       L->d=l;

		       l->s=L;

		       l=L;

		  } }

     L=L->d;





  }



}



void flood(int x,int k){

int d[1010],ii,jj;

nod *p;



  d[1]=x; s[x]=k;

  ii=1;jj=1;

  while(ii<=jj){

	p=v[d[ii]];

	while(p){

	   if(!s[p->x] && c[d[ii]][p->x]>f[d[ii]][p->x])

	   { s[p->x]=k;

	     d[++jj]=p->x; }

	p=p->d;

	}

  ii++;

  }

}





int main()

{

   READ();

   INIT();

   FLUX();

   flux=e[n];



   int i;

   for(i=1;i<=n;i++) s[i]=0;

   flood(1,1);

   flood(n,-1);



   int nr=0;

   for(i=1;i<=m;i++)

       if(s[lx[i]]*s[ly[i]]==-1) {nr++; lx[i]=-1; }

 /*     else if(c[ lx[i] ][ ly[i] ]==f[ lx[i] ][ ly[i] ] || c[ lx[i] ][ ly[i] ]==-f[ lx[i] ][ ly[i] ]){

      c[ lx[i] ][ ly[i] ]++;

      c[ ly[i] ][ lx[i] ]++;

      INIT();

      FLUX();

      c[ lx[i] ][ ly[i] ]--;

      c[ ly[i] ][ lx[i] ]--;

      if(flux<e[n]) { lx[i]=-1; nr++;  }

{1}

   }*/



   FILE *g;

   g=fopen("critice.out","w");

   fprintf(g,"%d\n",nr);

   for(i=1;i<=m;i++)

     if(lx[i]==-1) fprintf(g,"%d\n",i);

   fclose(g);

return 0;

}