1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
#include<bits/stdc++.h>
using namespace std;

int n, m, k, a, it, koniec, PI[1003];
vector<int> v[1003], s[2], W;
vector<int>::iterator iT;

bool spr(){
    for( int i = 0; i<=m; i++ )
        PI[i] = 0;
    int k = 0;
    for( int q = 2; q<=m; q++ ){
        while( k>0 && W[k+1]!=W[q])
            k = PI[k];
        if( W[k+1]==W[q] )
            k++;
        PI[q] = k;
    }

    int q = 0;
    for( int i = 1; i<s[0].size(); i++ ){
        while( q>0 && W[q+1]!=s[0][i] )
            q = PI[q];
        if( W[q+1]==s[0][i] )
            q++;
        if( q==m ){
            return true;
        }
    }
    for( int i = 1; i<s[1].size(); i++ ){
        while( q>0 && W[q+1]!=s[1][i] )
            q = PI[q];
        if( W[q+1]==s[1][i] )
            q++;
        if( q==m ){
            return true;
        }
    }
    return false;
}

int main()
{
    scanf("%d%d", &n, &m);
    for( int i = 1; i<=n; i++ ){
        scanf("%d", &k);
        while( k-- ){
            scanf("%d", &a);
            v[i].push_back(a);
        }
    }
    W.push_back(0);
    for( int i = 1; i<=m; i++ ){
        scanf("%d", &a);
        W.push_back(a);
    }
    s[0].push_back(1);
    bool rl = false;

    for( int i = 1; i<=10004; i++ ){
        if( spr() ){
            printf("%d\n", i);
            return 0;
        }
        if( !rl ){
            for( int j = 0; j<s[0].size(); j++ )
                for( int l = 0; l<v[s[0][j]].size(); l++ )
                    s[1].push_back(v[s[0][j]][l]);
            rl = true;
            s[0].clear();
            s[0].push_back(0);
        }
        else{
            for( int j = 0; j<s[1].size(); j++ )
                for( int l = 0; l<v[s[1][j]].size(); l++ )
                    s[0].push_back(v[s[1][j]][l]);
            rl = false;
            s[1].clear();
            s[1].push_back(0);
        }
    }
    printf("-1\n");
    return 0;
}