Go: package main

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

func configure(scanner *bufio.Scanner) {
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
}
func getNextString(scanner *bufio.Scanner) string {
	scanned := scanner.Scan()
	if !scanned {
		panic("scan failed")
	}
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	extra := 0
	if os.Getenv("I") == "IronMan" {
		fp, _ = os.Open(os.Getenv("END_GAME"))
		extra = 100
	}
	scanner := bufio.NewScanner(fp)
	configure(scanner)
	writer := bufio.NewWriter(wfp)
	defer func() {
		r := recover()
		if r != nil {
			fmt.Fprintln(writer, r)
		}
		writer.Flush()
	}()
	solve(scanner, writer)
	for i := 0; i < extra; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	for n := getNextInt(scanner); n > 0; n = getNextInt(scanner) {
		tt := make([]team, n)
		for i := 0; i < n; i++ {
			tt[i].id = getNextInt(scanner)
			tt[i].uni = getNextInt(scanner)
			tt[i].ac = getNextInt(scanner)
			tt[i].pn = getNextInt(scanner)
		}
		sort.SliceStable(tt, func(i, j int) bool {
			if tt[i].ac == tt[j].ac {
				if tt[i].pn == tt[j].pn {
					return tt[i].id < tt[j].id
				}
				return tt[i].pn < tt[j].pn
			}
			return tt[i].ac > tt[j].ac
		})
		cc := make([]int, 100005)
		ans := make([]int, 0)
		for i := 0; i < n; i++ {
			if cc[0] < 10 && cc[tt[i].uni] < 3 {
				cc[0]++
				cc[tt[i].uni]++
				ans = append(ans, tt[i].id)
				continue
			}
			if cc[0] < 20 && cc[tt[i].uni] < 2 {
				cc[0]++
				cc[tt[i].uni]++
				ans = append(ans, tt[i].id)
				continue
			}
			if cc[0] < 26 && cc[tt[i].uni] < 1 {
				cc[0]++
				cc[tt[i].uni]++
				ans = append(ans, tt[i].id)
				continue
			}
		}
		for i := 0; i < len(ans); i++ {
			fmt.Fprintln(writer, ans[i])
		}
	}
}

type team struct {
	id, uni, ac, pn int
}

C++: #include<iostream>
#include<vector>
#include<string.h>
#include<algorithm>
using namespace std;

struct Team{
  int id,org,ans,pen;
  Team(int id,int org,int ans,int pen) : id(id), org(org), ans(ans), pen(pen) { }
};

bool operator<(const Team &t, const Team &s) {
  return t.ans!=s.ans ? t.ans>s.ans : t.pen!=s.pen ? t.pen<s.pen :
  t.id<s.id;
}

int org[1001];

int main() {
  int n,d,I,A,U,P;
  while(cin>>n, n) {
    memset(org, 0, sizeof(org));
    d=0;
    vector<Team> v;
    for(int i=0; i<n; ++i) {
      cin>>I>>U>>A>>P;
      v.push_back( Team(I,U,A,P) );
    }

    sort(v.begin(), v.end());

    int c=0;
    while(d<26) {
      if(d<10) {
	if(org[v[c].org]<=2) {
	  d++;
	  cout<<v[c].id<<endl;
	  org[v[c].org]++;
	}
      }else if(d<20)
	if(org[v[c].org]<=1) {
	  d++;
	  cout<<v[c].id<<endl;
	  org[v[c].org]++;
	}
      else
	if(org[v[c].org]==0) {
	  d++;
	  cout<<v[c].id<<endl;
	  org[v[c].org]++;
	}
      c++;
      if(c == v.size()) break;
    }
  }
}

C++: #include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define RFOR(i,a,b) for(int i=(b) - 1;i>=(a);i--)
#define REP(i,n) for(int i=0;i<(n);i++)
#define RREP(i,n) for(int i=n-1;i>=0;i--)

#define PB push_back
#define MP make_pair
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define CLR(a) memset(a,0,sizeof(a))
#define SET(a,c) memset(a,c,sizeof(a))

#define DEBUG(x) cout<<"#x"<<": "<<x<<endl

using namespace std;

typedef long long int ll;
typedef vector<int> vi;
typedef vector<ll> vl;

const ll INF = INT_MAX/3;
const ll MOD = 1000000007;
const double EPS = 1e-14;
const int dx[] = {1,0,-1,0} , dy[] = {0,1,0,-1};

map<int,bool> used;
map<int,int> count_t;
map<int,bool> isDecided;
vector<bool> ans;

int main(){
    while(true){
	int n;
	vector< pair< pair<int,int> , pair<int,int> > > t;
	cin >> n;
	if(n==0) break;
	REP(i,n){
	    int I,A,U,P;
	    cin >> I >> U >> A >> P;
	    t.PB( MP( MP(-A,P) , MP(I,U) ) );
	    used[I] = false;
	    count_t[U] = false;
	    isDecided[I] = false;
	    sort(ALL(t));
	}
	int temp = 0;

	REP(i,n){
	    if(!used[t[i].second.second]){
		used[t[i].second.second] = true;
		count_t[t[i].second.second]++;
		isDecided[t[i].second.first] = true;
		temp++;
	    }
	}

	if(temp < 10){
	    REP(i,n){
		if(!isDecided[t[i].second.first] && count_t[t[i].second.second] < 3){
		    count_t[t[i].second.second]++;
		    isDecided[t[i].second.first] = true;
		    temp++;
		}
	    }
	}


	if(temp < 20){
	    REP(i,n){
		if(!isDecided[t[i].second.first] && count_t[t[i].second.second] < 2){
		    count_t[t[i].second.second]++;
		    isDecided[t[i].second.first] = true;
			temp++;
		}
	    }
	}

	if(temp < 26){
	    REP(i,n){
		if(!isDecided[t[i].second.second] && count_t[t[i].second.second] < 1){
		    count_t[t[i].second.second]++;
		    isDecided[t[i].second.first] = true;
		    temp++;
		}
	    }
	}

	REP(i,n){
	    if(isDecided[t[i].second.first]) cout << t[i].second.first << endl;
	}
    }

    return 0;
}

C++: #include <iostream>
#include <set>

using namespace std;

struct comparator {
  bool operator() (const int *lhs, const int *rhs) const{
    if (lhs[2] == rhs[2] && lhs[3] == rhs[3])
      return lhs[0] < rhs[0];
    else if (lhs[2] == rhs[2])
      return lhs[3] < rhs[3];
    else
      return lhs[2] > rhs[2];
  }
};

int main(int argc, char *argv[]) {
  int n;
  set<int*, comparator> team;
  set<int> result;
  while (true) {
    cin >> n;
    if (n == 0)
      break;
    for (int i = 0; i < n; i++) {
      int *tmp = new int[4];
      cin >> tmp[0] >> tmp[1] >> tmp[2] >> tmp[3];
      team.insert(tmp);
    }

    for (set<int*>::iterator itr = team.begin();
         itr != team.end(); itr++) {
      //cout << (*itr)[0];                                                                                                                                                
      if (result.size() < 10 && result.count((*itr)[1]) < 3) {
        cout << (*itr)[0] << endl;
        result.insert((*itr)[1]);
      } else if (result.size() < 20 && result.count((*itr)[1]) < 2) {
        cout << (*itr)[0] << endl;
        result.insert((*itr)[1]);
      } else if (result.size() < 26 && result.count((*itr)[1]) < 1) {
        cout << (*itr)[0] << endl;
        result.insert((*itr)[1]);
      }
    }
    team.clear();
    result.clear();
  }
  return 0;
}