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>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cstring>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <numeric>
#include <utility>
#include <iomanip>
#include <algorithm>
#include <functional>
using namespace std;

typedef long long ll;
typedef vector<int> vint;
typedef vector<long long> vll;
typedef pair<int,int> pint;
typedef pair<long long, long long> pll;

#define MP make_pair
#define PB push_back
#define ALL(s) (s).begin(),(s).end()
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P) 
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P) 
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P) 
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s << endl; }



int n;
int m, k;
int per, ans;

int main() {
    while (cin >> n) {
        if (n == 0) break;
        
        vint persons[150];
        for (int i = 0; i < n; ++i) {
            persons[i].clear();
            cin >> m;
            for (int j = 0; j < m; ++j) {
                cin >> per; persons[i].PB(per);
            }
            sort(ALL(persons[i]));
        }
        cin >> k;
        vint answer;
        for (int i = 0; i < k; ++i) {
            cin >> ans; answer.PB(ans);
        }
        
        int con[150];
        memset(con, 0, sizeof(con));
        
        for (int i = 0; i < answer.size(); ++i) {
            int l = answer[i];
            
            for (int j = 0; j < n; ++j) {
                if (binary_search(ALL(persons[j]), l)) {
                    con[j]++;
                }
            }
        }
        
        vint res;
        for (int i = 0; i < n; ++i) {
            if (con[i] == k) res.PB(i+1);
        }
        
        if (res.size() == 1) cout << res[0] << endl;
        else cout << -1 << endl;
    }
    
    return 0;
}

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;
  int c;
  int check;
  while(1){
    c=0;
    check=0;
    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]==0) c=2;
      if(r[b-1]==1){
	for(int j=0;j<N;j++){
	  if(p[j][b-1]==1){
	    if(check==j+1) break;
	    check=j+1;
	    c++;
	    break;
	  }
	}
      }
    }
    if(c!=1) cout<<-1<<endl;
    else cout<<check<<endl;
    }
  return 0;
}

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

int N, leak[100];
bool memberInf[101][101];

void init(int N){
  for(int i = 1; i <= N; i++) for(int j = 1; j <= N; j++)
    memberInf[i][j] = false;
}

int main(void){
  while(cin >> N && N != 0){
    init(N);
    for(int i = 1; i <= N; i++){
      int M; cin >> M;
      for(int j = 0; j < M; j++){
        int p; cin >> p;
        memberInf[i][p] = true;
      }
    }
    int K; cin >> K;
    for(int i = 0; i < K; i++) cin >> leak[i];
    
    int ans = -1, cnt = 0;
    for(int i = 1; i <= N; i++){
      bool judge = true;
      for(int j = 0; j < K; j++){
        if(!memberInf[i][leak[j]]) { judge = false; break; }
      }
      if(judge){ ans = i; cnt++; }
      if(cnt >= 2){ ans = -1; break; }
    }
    cout << ans << endl;
  }
  return 0;
}