#include <stdio.h>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <deque>
#include <string.h>

using namespace std;

typedef pair<int, int> PII;

#ifdef _WIN32
#define TYPEOF decltype
#else
#define TYPEOF typeof
#endif

#define FOR(i,s,e) for(int i = s;i < e; i++)
#define TR(i, c) for(TYPEOF(c.begin()) i = c.begin(); i != c.end(); ++i)
#define TRS(i, c, ...) TR(__itr, c) { TYPEOF(*c.begin()) &i = *__itr;  __VA_ARGS__ }
#define TRP(f, s, c, ...) TR(__itr, c) { TYPEOF(c.begin()->first) &f = __itr->first; TYPEOF(c.begin()->second) &s = __itr->second;  __VA_ARGS__ }

#define NMAX 1024

int C[NMAX][NMAX];
int F[NMAX][NMAX];
int P[NMAX];
int Q[NMAX];
int viz[NMAX];
int idx[NMAX][NMAX];

vector<int> G[NMAX];

int N,M;

bool not_visited_endpoint(PII p) {
	if(viz[p.first] || viz[p.second])
		return false;
	return true;
}

int bfs() {

	int s = 0, e = 1;
	Q[0] = 1;
	memset(viz, 0, (N+1) * sizeof(int));
	viz[1] = 1;

	while(s < e) {
		int na = Q[s++];
		if(na == N) continue;
		FOR(i,0,G[na].size()) {
			int nb = G[na][i];
			if(viz[nb] || C[na][nb] == F[na][nb]) continue;
			viz[nb] = 1;
			P[nb] = na;
			Q[e++] = nb;
		}
	}

	return viz[N];
}

#define INF 0x3f3f3f3f

int main()
{
#if 1
	freopen("critice.in", "r", stdin);
#ifndef MY_STUFF
	freopen("critice.out", "w", stdout);
#endif
#endif

	scanf("%d %d", &N, &M);

	FOR(i,0,M) {
		int x,y,c;
		scanf("%d %d %d", &x, &y, &c);
		C[x][y] = c;
		C[y][x] = c;
		idx[x][y] = i+1;
		idx[y][x] = i+1;
		G[x].push_back(y);
		G[y].push_back(x);
	}

	int flow, fmin;

	for(flow = 0; bfs(); )
		FOR(i, 0, G[N].size()) {
			int nod = G[N][i];
			if(!viz[nod] || C[nod][N] == F[nod][N]) continue;
			P[N] = nod;
			fmin = INF;
			for(int nod = N; nod != 1; nod = P[nod]) {
				int c = C[ P[nod] ][nod], f = F[ P[nod] ][nod];
				fmin = min(fmin, c - f);
			}
			for(int nod = N; nod != 1; nod = P[nod]) {
				F[ P[nod] ][nod] += fmin;
				F[nod][ P[nod] ] -= fmin;
			}
			flow += fmin;
		}

	//printf("%d\n", flow);

	set<PII> a;
	FOR(i,1,N)
		FOR(j,1,N)
			if(C[i][j] > 0 && F[i][j] == C[i][j]) {
				a.insert(PII(i,j));
				C[i][j] = 0;
			}

	int s = 0, e = 1;
	Q[0] = 1;
	memset(viz, 0, (N+1) * sizeof(int));
	viz[1] = 1;
	while(s<e) {
		int na = Q[s++];
		FOR(i,0,G[na].size()) {
			int nb = G[na][i];
			if(viz[nb]) continue;
			if(C[na][nb] == 0) continue;
			viz[nb] = 1;
			Q[e++] = nb;
		}
	}

	remove_if(a.begin(), a.end(), not_visited_endpoint);
	
	printf("%d\n", a.size());
	TRS(i, a,
		printf("%d\n", idx[i.first][i.second]);
	)

	return 0;
}