#include<bits/stdc++.h>
using namespace std;
const int N=110,inf=0x7f;
typedef pair<int,int> pii;
int n,a,b;
vector<pii> tu[N];
deque<int> pq;
int dis[N];
bool flag=false;
bool vis[N];
void bfs(){
	int cur;
	dis[a]=0;
	pq.push_front(a);
	while(!pq.empty()){
		cur=pq.front();
		pq.pop_front();
		if(vis[cur]) continue;
		vis[cur]=true;
		if(cur==b) flag=true;
		for(auto vv:tu[cur]){
			if( dis[cur]+vv.first<dis[vv.second] && cur!=vv.second ){
				dis[vv.second] = dis[cur] + vv.first;
				if(vv.first==0) pq.push_front(vv.second);
				else pq.push_back(vv.second);
			}
		}
	}
}
int main(){
	//freopen("")
	cin>>n>>a>>b;
	int k,v;
	memset(tu,inf,sizeof(tu));
	memset(dis,inf,sizeof(dis));
	memset(vis,false,sizeof(vis));
	for(int i=1;i<=n;i++){
		cin>>k;
		for(int j=1;j<=k;j++){
			cin>>v;
			if(j==1) tu[i].push_back({0,v});
			else tu[i].push_back({1,v});
		}
	}
	bfs();
	if(flag) cout<<dis[b]<<"\n";
	else cout<<-1<<"\n";
	return 0;
}