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 <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;

int main(){
    while(true){
	int n;
	vector< pair< pair<int,int> , pair<int,int> > > t;
	cin >> n;
	if(n==0) break;
	used.clear();
	count_t.clear();
	isDecided.clear();
	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));
// 	REP(i,n) printf("A: %d P: %d I: %d U: %d\n",-t[i].first.first,t[i].first.second,t[i].second.first,t[i].second.second);
	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 == 10) break;
	    }
	}


	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 == 20) break;
	    }
	}

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

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

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <map>

using namespace std;

class teamInfo{
public:
	int id;
	int u;
	int a;
	int p;

	bool operator<(teamInfo &ti){
		if(ti.a < this->a)
			return true;
		else if(ti.a > this->a)
			return false;
		else{
			if(ti.p < this->p)
				return false;
			else if(ti.a > this->a)
				return true;
			else{
				if(ti.id > this->id)
					return true;
				else
					return false;
			}
		}
	}
};

int main(){

	int n;
	while(cin >> n && n !=0){
		vector<teamInfo> v;
		map<int,int> ucnt;

		for(int i = 0; i < n; i++){
			teamInfo ti;
			cin>>ti.id>>ti.u>>ti.a>>ti.p;
			v.push_back(ti);
		}
		sort(v.begin(),v.end());

		for(int i = 0; i < n; i++){
			if(i < 10){
				ucnt[v[i].u]++;
				if(ucnt[v[i].u] >= 4){
					ucnt[v[i].u]--;
				}
				else
					cout << v[i].id << endl;
			}
			else if(i < 20){
				ucnt[v[i].u]++;
				if(ucnt[v[i].u] >= 3){
					ucnt[v[i].u]--;
				}
				else
					cout << v[i].id << endl;
			}
			else if(i < 26){
				ucnt[v[i].u]++;
				if(ucnt[v[i].u] >= 2){
					ucnt[v[i].u]--;
				}
				else
					cout << v[i].id << endl;
			}
		}
	}

	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
int n,sc[10010];
struct Set{
  int I,U,A,P;
};
bool comp(const Set& a, const Set& b){
  if(a.A!=b.A){
    return a.A>b.A;
  }else{
    return a.P<b.P;
  }
}
vector<Set> vec;
void el(int x){
  sc[vec[x].U]++;
  cout<<vec[x].I<<endl;
}
int main(){
  while(1){
    cin>>n;
    for(int i=0;i<10010;i++)sc[i]=0;
    vec.clear();
    if(n==0)break;
    for(int i=0;i<n;i++){
      Set t;
      cin>>t.I>>t.U>>t.A>>t.P;
      vec.push_back(t);
    }
    sort(vec.begin(),vec.end(),comp);
    for(int i=0;i<min(26,n);i++){
      if(i<10){
	if(sc[vec[i].U]<3)el(i);
      }else if(i<20){
	if(sc[vec[i].U]<2)el(i);
      }else{
	if(sc[vec[i].U]==0)el(i);
      }
    }
  }
  return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <cstring>
#include <cmath>
#include <queue>
#include <map>
#include <set>
using namespace std;

#define rep(i,n) for(int i=0; i<n; i++)
#define FOR(i,s,n) for(int i=s; i<n; i++)
#define ALL(x) x.begin(), x.end()
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

int passed[1001];

struct team {
	int i, u, a, p;
	team(int I, int U, int A, int P) {
		i = I;
		u = U;
		a = A;
		p = P;
	}
};

bool operator<(const team& l, const team& r) {
	if( l.a == r.a ) {
		if( l.p == r.p ) {
			return l.i < r.i;
		}
		return l.p < r.p;
	}
	return l.a > r.a;
}

int main() {
	int n;
	while(cin >> n, n) {
		memset(passed, 0, sizeof(passed));
		vector<team> t;
		rep(i, n) {
			int I, U, A, P;
			cin >> I >> U >> A >> P;
			t.push_back( team(I,U,A,P) );
		}
		sort( t.begin(), t.end() );
		vector<int> id;
		rep(i, n) {
			if(id.size() < 10) {
				if( passed[t[i].u] < 3 ) {
					id.push_back(t[i].i);
					passed[t[i].u]++;
				}
			}
			else if(id.size() < 20) {
				if( passed[t[i].u] < 2 ) {
					id.push_back(t[i].i);
					passed[t[i].u]++;
				}
			}
			else if(id.size()<26) {
				if( passed[t[i].u] < 1 ) {
					id.push_back(t[i].i);
					passed[t[i].u]++;
				}
			}
		}
		rep(i, id.size()) {
			cout << id[i] << endl;
		}
	}
	return 0;
}