```cpp
#include <bits/stdc++.h>
using namespace std;
int f[210][210],n,m,a,b;
int main()
{
    cin>>n>>a>>b;
    memset(f,1000000009,sizeof(f));
    for(int i=1;i<=n;i++){
      int m;
      cin>>m;
      int l;
      for(int j=1;j<=m;j++){
        cin>>l;f[i][l]=1;
        if(j==1)f[i][l]=0;}
      f[i][i]=0;
    }
    for (int k = 1; k <= n; k ++ )
        for (int i = 1; i <= n; i ++ )
            for (int j = 1; j <= n; j ++ )
                if(i!=j&&j!=k&&i!=k)
                f[i][j] = min(f[i][j], f[i][k] + f[k][j]);
    if(f[a][b]==1000000009)
    cout<<"-1";
    else 
    cout<<f[a][b];
 	return 0;//orz
}