#include <vector>
#include <queue>
#include <stack>
#include <list>
#include <set>
#include <algorithm>
#include <utility>
#include <string>
#include <functional>
#include <sstream>
#include <fstream>
#include <iostream>
using namespace std;
#define FOR(i,a,b) for (i=a;i<=b;i++)
#define fori(it,v) for (it=(v).begin();it!=(v).end();it++)
#define pb push_back
#define mp make_pair
#define fs first
#define ss second
#define all(c) c.begin(),c.end()
#define pf push_front
#define popb pop_back
#define popf pop_front
int main()
{
	FILE *in,*out;
	in=fopen("critice.in","r");
	out=fopen("critice.out","w");
	fscanf(in,"%d%d",&n,&m);
	FOR(i,1,m)
	{
		fscanf(in,"%d%d%d",&x,&y,&z);
		b.pb(mp(x,y));
		a[x].pb(y);
		a[y].pb(x);
		cap[x][y]=cap[y][x]=z;
	}
	while (flux());
	bfss();
	bfsd();
	FOR(i,0,m-1)
	{
		if ((vs[b[i].fs]&&vd[b[i].ss]&&cap[b[i].fs][b[i].ss]==0)||(vs[b[i].ss]&&vd[b[i].fs]&&cap[b[i].ss][b[i].fs]==0))
			fprintf(out,"%d\n",i);
	}
	fclose(in);
	fclose(out);
	return 0;
}