C++ :

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

#define N 10

struct edge {
	int v, next, num;
} E[N*2];

int n, m, p[N], Ind, deep[N], ancestor[N], mark[N], c[N*2], tn;

int dfs(int s, int e, int fnum, int d) {
	mark[s] = 1;
	deep[s] = ancestor[s] = d;
	int z = 0;
	int ok = 0, tmp;
	if (s == e)
		ok = 1;
	for (int i = p[s]; i != -1; i = E[i].next) {
		if (E[i].num == fnum)
			continue;
		tmp = 0;
		if (mark[E[i].v])
			ancestor[s] = min(ancestor[s], deep[E[i].v]);
		else {
			tmp = dfs(E[i].v, e, E[i].num, d + 1);
			ancestor[s] = min(ancestor[s], ancestor[E[i].v]);
			z++;
			if (tmp) {
				if (ancestor[E[i].v] > deep[s])
					c[tn++] = E[i].num;
				ok = 1;
			}
		}
	}
	return ok;
}

int main() {
	int a, b, i, s, e;
	while (scanf("%d%d", &n, &m) != EOF) {
		memset(p, -1, sizeof(p));
		Ind = 0;
		for (i = 0; i < m; i++) {
			scanf("%d%d", &a, &b);
			E[Ind].v = b;
			E[Ind].num = i;
			E[Ind].next = p[a];
			p[a] = Ind++;

			E[Ind].v = a;
			E[Ind].num = i;
			E[Ind].next = p[b];
			p[b] = Ind++;
		}
		scanf("%d%d", &s, &e);
		tn = 0;
		memset(mark, 0, sizeof(mark));
		dfs(s, e, -1, 1);
		sort(c, c + tn);
		printf("%d\n", tn);
		for (i = 0; i < tn; i++)
			printf(i == tn - 1 ? "%d\n" : "%d ", c[i]);
	}
	return 0;
}