#include <stdio.h>

const char iname[] = "critice.in";
const char oname[] = "critice.out";

#define MAX_N 1001
#define MAX_M 10000

int n, *G[MAX_N], m, E[MAX_N][2], deg[MAX_N], C[MAX_N][MAX_N], F[MAX_N][MAX_N];

int Q[MAX_N], P[MAX_N], mark[MAX_N];


void read_in(void)
{
	int x, y, c;

	FILE *fi = fopen(iname, "r");

	fscanf(fi, "%d", &n);
	fscanf(fi, "%d", &m);
	for (int i = 0; i < m; ++ i) 
	{
		fscanf(fi, "%d %d %d", &x, &y, &c);
		C[x][y] = C[y][x] = c;
		E[i][0] = x;
		E[i][1] = y;
		deg[x] ++, deg[y] ++;
	}
	for (int i = 1; i <= n; ++ i) 
	{
		G[i] = new int [deg[i] + 1];
		G[i][deg[i]] = -1;
		deg[i] = 0;
	}
	for (int i = 0; i < m; ++ i) 
	{
		x = E[i][0];
		y = E[i][1];
		G[x][deg[x] ++] = y;
		G[y][deg[y] ++] = x;
	}
	fclose(fi);
}

int BFS(void)
{
	int head, tail, x, *p;

	for (int i = 2; i <= n; ++ i) 
		P[i] = -1;
	head = tail = 0;
	Q[head] = 1;

	while (head <= tail)
	{
		x = Q[head];
		p = G[x];
		while (*p != -1)
		{
			if (P[*p] == -1 && C[x][*p] - F[x][*p] > 0)
			{
				P[*p] = x;
				Q[++ tail] = *p;
				if (*p == n)  
					return 1;
			}
			p ++;
		}
		head ++;
	}
	return 0;
}

void BF1(int start, int val)
{
     int cap, coada, nr, *p;
     
     cap = coada = 1;
     Q[cap] = start;
     mark[start] = val;
     
     while (cap <= coada)
     {
           nr = Q[cap];
           p = G[nr];
           while (*p != -1)
           {
                 if (mark[*p] != val && (C[nr][*p] - F[nr][*p]) > 0)
                 {
                              mark[*p] = val;
                              coada++;
                              Q[coada] = *p;
                 }
                 ++p;
           }
           ++cap;
     }
}

void BF2(int start, int val)
{
     int cap, coada, nr, *p;
     
     cap = coada = 1;
     Q[cap] = start;
     mark[start] = val;
     
     while (cap <= coada)
     {
           nr = Q[cap];
           p = G[nr];
           while (*p != -1)
           {
                 if (mark[*p] != val && (C[*p][nr] - F[*p][nr]) > 0)
                 {
                              mark[*p] = val;
                              coada++;
                              Q[coada] = *p;
                 }
                 ++p;
           }
           ++cap;
     }
}

int main(void)
{
	read_in();
	
	while (BFS())
	{
//		printf("BFS\n");
		for (int i = 1; i <= n; ++ i)
		{
			if (P[i] == -1 || C[i][n] <= F[i][n])
				continue ;
			int r = C[i][n] - F[i][n];
			for (int j = i; j != 1; j = P[j])
			{
				if (r > C[P[j]][j] - F[P[j]][j])
					r = C[P[j]][j] - F[P[j]][j];
			}
			if (r == 0)
				continue ;
//			printf("way %d, ", i);
			F[i][n] += r, F[n][i] -= r;
			for (int j = i; j != 1; j = P[j]) 
			{
				F[P[j]][j] += r;
				F[j][P[j]] -= r;
//				printf("%d ", P[j]);
			}
		}
//		printf("\n---\n");
	}

	FILE *fo = fopen(oname, "w");

	for (int i = 1; i <= n; ++ i)
		P[i] = -1;
	BF1(1, 1);
	BF2(n, 2);
	int res = 0;
	for (int i = 0; i < m; ++ i) 
	{
		int x = E[i][0];
		int y = E[i][1];
		if (P[x] + P[y] == 3)
			res ++;
	}
	fprintf(fo, "%d\n", res);
	for (int i = 0; i < m; ++ i) 
	{
		int x = E[i][0];
		int y = E[i][1];
		if (P[x] + P[y] == 3)
			fprintf(fo, "%d\n", i + 1);
	}
	fclose(fo);

	return 0;
}