Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()

	for {
		N := io.NextInt()
		if N == 0 {
			break
		}
		set := make([]map[int]struct{}, N)
		for i := 0; i < N; i++ {
			set[i] = make(map[int]struct{})
			M := io.NextInt()
			for j := 0; j < M; j++ {
				p := io.NextInt()
				set[i][p] = struct{}{}
			}
		}
		K := io.NextInt()
		l := make([]int, K)
		for i := 0; i < K; i++ {
			l[i] = io.NextInt()
		}

		ans := 0
	FOR_OUTER:
		for i := 0; i < N; i++ {
			for j := 0; j < K; j++ {
				if _, f := set[i][l[j]]; f == false {
					continue FOR_OUTER
				}
			}
			switch ans {
			case 0:
				ans = i + 1
			default:
				ans = -1
			}
		}
		if ans > 0 {
			io.Println(ans)
		} else {
			io.Println(-1)
		}
	}
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: #include <iostream>
using namespace std;


int main(){
    while (1){
    int m, n = 0;
    bool member[101][101] = {{false}}; // who knows who

    cin >> n;
    if (n == 0) break;
    for (int i = 1; i <= n; i++){
	cin >> m;
	for (int j = 1; j <= m; j++){
	    int tmp;
	    cin >> tmp;
	    member[i][tmp] = true;
	}
    }

    int k;
    cin >> k;
    int ohno[101] = {false};
    for (int i = 0; i < k; i++){
	int tmp;
	cin >> tmp;
	ohno[tmp] = true;
    }
    int many = 0;

    bool theOne = true;
    int mem = 0;
    for (int j = 1; j <= n; j++){
	theOne = true;
	for (int i = 1; i <= n; i++){ // member
	    if (ohno[i]){
		if (!member[j][i]) theOne = false;
	    }
	}
	if (theOne){
	    many++;
	    mem = j;
	}
    }
    
    if (many == 1) cout << mem << endl;
    else cout << -1 << endl;
    }
}

C++: #include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<functional>
#include<numeric>
#include<queue>
#include<stack>
using namespace std;
#define all(c) (c).begin(), (c).end()
#define rep(i,n) for(int i=0; i<(int)(n); i++)


int main() {
	int n;
	while(cin >> n, n) {
		vector<vector<int> > ms(n, vector<int>());
		for(int i = 0; i < n; i++) {
			int m;
			cin >> m;
			for(int j = 0; j < m; j++) {
				int mss;
				cin >> mss;
				mss--;
				ms[i].push_back(mss);
			}
		}
		int k;
		cin >> k;
		vector<int> led(n);
		for(int i = 0; i < k; i++) {
			int j;
			cin >> j;
			j--;
			led[j] = 1;
		}
		bool summable = true;
		// fill one
		int kouho = -1;
		for(int i = 0; i < n; i++) {
			int count = 0;
			for(int j = 0; j < ms[i].size(); j++) {
				if(led[ms[i][j]]) count++;
			}
			if (count == k) {
				if (kouho != -1) {
					cout << -1 << endl;
					goto end_loop;
				}
				kouho = i;
			}
		}
		// fill some
		for(int i = 0; i < n; i++) {
			if (i == kouho) continue;
			for(int j = 0; j < ms[i].size(); j++) {
					led[ms[i][j]] = 2;
			}
		}
		
		for(int i = 0; i < n; i++) {
			if (led[i] == 1) {
				summable = false;
				break;
			}
		}
		if (summable || kouho == -1) {
			cout << -1 << endl;
		}
		else {
			cout << kouho+1 << endl;
		}
		
		end_loop: {}
	}
	
	return 0;
}

C++: #include <iostream>
#include <cstdlib>
#include <vector>
#include <set>
using namespace std;
const static int N_MAX = 110;
const static int N_A = 0;
const static int ERR = -9999;

int main() {
  while( 1 ) {
    int n;
    vector< set<int> > table;
    bool possible[ N_MAX ];
    
    cin >> n;
    if( !n ) { return EXIT_SUCCESS; }

    set<int> dummy;
    table.push_back( dummy );
    for( int i = 1; i <= n; i++ ) {
      int m;
      cin >> m;
      set<int> s;
      possible[ i ] = true;
      for( int j = 0; j < m; j++ ) {
        int p;
        cin >> p;
        s.insert( p );
      }
      table.push_back( s );
    }


    int k;
    cin >> k;
    for( int i = 0; i < k; i++ ) {
      int l;
      cin >> l;
      for( int j = 1; j <= n; j++ ) {
        if( !possible[ j ] ) { continue; }
        if( table[ j ].find( l ) == table[ j ].end() ) {
          possible[ j ] = false;
        }
      }
    }
    
    int ans = -1;
    
    for( int i = 1; i <= n; i++ ) {
      if( possible[ i ] ) {
        if( ans == -1 ) {
          ans = i;
        } else {
          ans = ERR;
        }
      }
    }

    if( ans == ERR ) { ans = -1; };

    cout << ans  << endl;
  }
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
  int N;
  int a,b;
  int r[100];
  int s[100];
  int p[100][100];
  int sum;
  bool c=false;
  while(1){
    c=false;
    for(int i=0;i<100;i++){
      for(int j=0;j<100;j++){
	p[i][j]=0;
      }
    }
    cin>>N;
    if(N==0) break;
    for(int i=0;i<N;i++){
      cin>>a;
      if(a==0) continue;
      for(int j=0;j<a;j++){
	cin>>b;
	p[i][b-1]=1;
      }
    }
    for(int i=0;i<N;i++){
      sum=0;
      for(int j=0;j<N;j++){
	sum+=p[j][i];
      }
      r[i]=sum;
    }
    cin>>a;
    for(int i=0;i<a;i++){
      cin>>b;
      if(r[b-1]==1){
	for(int j=0;j<N;j++){
	  if(c==true) break;
	  if(p[j][b-1]==1){
	    cout<<j+1<<endl;
	    c=true;
	    break;
	  }
	}
      }
    }
    if(c==false) cout<<-1<<endl;
    }
  return 0;
}

C++: #include <stdio.h>
#include <string.h>

#pragma warning(disable : 4996)

int N, M, K, P, L[100]; bool ok[100][100];

int main()
{
	while (true)
	{
		scanf("%d", &N);

		if (N == 0) break;

		memset(ok, false, sizeof(ok));

		for (int i = 0; i < N; i++)
		{
			scanf("%d", &M);

			for (int j = 0; j < M; j++)
			{
				scanf("%d", &P);

				ok[i][P - 1] = true;
			}
		}

		scanf("%d", &K);

		for (int i = 0; i < K; i++) scanf("%d", &L[i]);

		int count_ = 0, ptr = -1;

		for (int i = 0; i < N; i++)
		{
			bool flag = true;

			for (int j = 0; j < K; j++)
			{
				if (!ok[i][L[j] - 1])
				{
					flag = false; break;
				}
			}

			if (flag)
			{
				count_++; ptr = i + 1;
			}
		}

		printf("%d\n", count_ == 1 ? ptr : -1);
	}

	return 0;
}