#include<cstdio>
#include<cstring>
#include<vector>
const int N = 1000 + 5, NODE = 10 + 5;

using namespace std;

struct Edge{
	int id, to;
	Edge() {}
	Edge(int id, int to) : id(id), to(to) {}
};

int n, c, t, idx;
int ans[N], deg[NODE];
vector<Edge> g[NODE];
bool used[N];

void dfs(int u)
{
	for(int i=0; i<(int)g[u].size(); ++i)
	{
		if(used[g[u][i].id]) continue;
		used[g[u][i].id] = true;
		dfs(g[u][i].to);
		ans[--idx] = g[u][i].id;
	}
}

void add_edge(int from, int to, int id)
{
	g[from].push_back(Edge(id, to));
}

void solve()
{
	bool flag = true;
	idx = n;
	
	if(g[t].empty() || deg[t]) flag = false;
	
	for(int i=1; i<NODE; ++i)
	{
		if(deg[i])
		{
			flag = false;
			break;
		}
	}
	
	if(flag) dfs(t);
	
	if(flag==false || idx != 0) printf("0\n");
	else
	{
		printf("1\n");
		if(c==2)
		{
			printf("%d", ans[0]);
			for(int i=1; i<n; ++i) printf(" %d", ans[i]);
			printf("\n");
		}
	}
}

int main()
{
	scanf("%d%d", &n, &c);
	scanf("%d", &t);
	memset(deg, 0, sizeof(deg));
	for(int i=0; i<n; ++i)
	{
		int from, to;
		scanf("%d%d", &from, &to);
		add_edge(from, to, i+1);
		++deg[from];
		--deg[to];
	}
	solve();
	
	return 0;
}