Go: ///
// File:  0529.go
// Author: ymiyamoto
//
// Created on Wed Feb 28 20:39:28 2018
//
package main

import (
	"fmt"
	"sort"
)

func max(n, m int) int {
	if n < m {
		return m
	} else {
		return n
	}
}

func main() {
	for {
		var N, M int
		fmt.Scan(&N, &M)
		if N == 0 && M == 0 {
			break
		}

		arr := make([]int, N+1)
		for i := 1; i <= N; i++ {
			fmt.Scan(&arr[i])
		}
		sort.Ints(arr)

		sums := make([]int, len(arr)*len(arr))
		for i := 0; i < len(arr); i++ {
			for j := 0; j < len(arr); j++ {
				sums[i+j] = arr[i] + arr[j]
			}
		}
		sort.Ints(sums)

		m := 0
		for i := 0; i < len(sums); i++ {
			rem := M - sums[i]
			if rem >= 0 {
				index := sort.Search(len(sums), func(i int) bool { return sums[i] > rem }) - 1
				if index >= 0 {
					m = max(m, sums[i]+sums[index])
				}
			}
		}
		fmt.Println(m)
	}
}

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

using namespace std;

int main ( void )
{
	int n, m;
	int p[1000];
	set<int> S;
	
	while ( cin >> n >> m, (n | m) )
	{
		int ans = 0;
		S.clear();
		for ( int i = 0; i < n; ++i )
        {
            cin >> p[i];
            if ( p[i] < m )
            {
                S.insert(p[i]);
                ans = max( ans, p[i] );
            }
        }
        for ( int i = 0; i < n; ++i )
        {
            for ( int j = i; j < n; ++j )
            {
                int x = p[i] + p[j];
                if ( x <= m )
                {
                    S.insert(x);
                    ans = max( ans, p[i] );
                }
            }
        }
        
        for ( int i = 0; i < n; ++i )
        {
            for ( int j = i; j < n; ++j )
            {
                int x = p[i] + p[j];
                if ( x <= m )
                {
                	int y = m - x;
                    set<int>::iterator it = lower_bound( S.begin(), S.end(), y );
                    if ( *it > y )	--it;
                    ans = max( ans, (x + *it) );
                }
            }
        }
		cout << ans << endl;
	}
	
	return 0;
}

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

using namespace std;

int main() {
  
  int n, m;
  
  while(cin >> n >> m && (n|m)) {
    int data[1002];
    int Q[10000005];
    
    n++;
    data[0] = 0;
    for(int i=1; i<n; i++) {
      cin >> data[i];
    }
    
    int T = 0;
    
    for(int i=0; i<n; i++) {
      Q[T++] = data[i];
    }
    
    for(int i=0; i<n; i++) {
      for(int j=0; j<n; j++) {
	Q[T++] = data[i] + data[j];
      }
    }
    
    sort(Q, Q+T);

    // for(int i=0; i<T; i++) cout << Q[i] << endl;
    
    int ans = 0;
    
    for(int i=0; i<T; i++) {
      int M = m - Q[i];
      if(M < 0) break;
      
      int lb = 0, ub = T;
      
      while(ub - lb > 1) {
	int mid = (lb + ub) / 2;
	
	if(Q[mid] <= M) {
	  lb = mid;
	} else {
	  ub = mid;
	}
      }
      ans = max(ans, Q[i]+Q[lb]);
    }
    
    cout << ans << endl;
  }
  
  return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int n,m,a[2000];
vector<int> t;
int main(){
  a[0]=0;
  while(cin>>n>>m&&n&&m){
    t.clear();
    for(int i=1;i<=n;i++)cin>>a[i];
    for(int i=0;i<n;i++){
      for(int j=i;j<=n;j++){
	t.push_back(-(a[i]+a[j]));
      }
    }
    sort(t.begin(),t.end());
    int ans=0;
    for(int i=0;i<(int)t.size();i++){
      int x=-t[i];
      int y=m-x;
      if(y<0)continue;
      vector<int> :: iterator it;
      it = lower_bound(t.begin(),t.end(),-y);
      if(it==t.end())continue;
      int z = *it;
      ans=max(ans,x-z);
    }
    cout<<ans<<endl;
  }
  return 0;
}

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

int N,M;
void solve()
{
	int res=0;
	vector<int>first,second;
	int temp;
	first.push_back(0);
	for(int i=0;i<N;i++)
	{
		scanf("%d",&temp);
		first.push_back(temp);
	}
	sort(first.begin(),first.end());
	for(int i=0;i<first.size();i++)
	{
		for(int j=i;j<first.size();j++)
		{
			if(first[i]+first[j]<=M)
			{
				second.push_back(first[i]+first[j]);
			}else{
				break;
			}
		}
	}
	sort(second.begin(),second.end());
	for(int i=0;i<second.size();i++)
	{
		int findV=M-second[i];
		int left=0,right=second.size()-1;
		int mid;
		int max_min=0;
		while(left<=right)
		{
			mid=(left+right)/2;
			if(findV<second[mid]){
				right=mid-1;
			}else{
				max_min=max(max_min,second[mid]);
				left=mid+1;
			}
		}
		res=max(res,max_min+second[i]);
	}
	printf("%d\n",res);
}

int main()
{
	while(true)
	{
		scanf("%d%d",&N,&M);
		if(N==0&&M==0)break;
		solve();
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i, s, n) for(int i = s; i < (int)n; ++i)
#define per(i, n) for(int i = n; i >= 0; i--)
#define ROF(i, s, n) for(int i = s; i >= (int)n; i--)
#define FORIT(i, A) for (auto i : A)
#define PRINT(x) cout << (x) << "\n"
#define SCAN(x) cin >> x
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define MP make_pair
#define PB push_back
#define EACH(i, n) for (__typeof((n).begin()) i = (n).begin(); i != (n).end(); ++i)
#define SZ(a) int((a).size())
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define CLR(a) memset((a), 0 ,sizeof(a))
#define NCLR(a) memset((a), -1 ,sizeof(a))
#define sq(n) (n) * (n)
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef complex<long double> P;
typedef long long LL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef priority_queue<int> maxpq;
typedef priority_queue< int, vector<int>, greater<int> > minpq;
typedef complex<double> Point;
static const double EPS = 1e-10;
static const double PI = acos( -1.0 );
static const int mod = 1000000007;
static const int INF = 1 << 29;
static const LL LL_INF = 1ll << 60;
static const int dx[] = { -1, 0, 1, 0, 1, -1, 1, -1 };
static const int dy[] = { 0, -1, 0, 1, 1, 1, -1, -1 };

#ifdef WIN32
#define dump(x) cerr << #x << " = " << (x) << "\n"
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << "\n"
#else
#define dump(x)
#define debug(x)
#endif

template<class T> ostream &operator<<( ostream &os, vector<T> &v ) {
  for ( int i = 0; i < v.size(); i++ ) {
    if ( i ) os << " ";
    os << v[ i ];
  }
  return os;
}

int main() {
  ios::sync_with_stdio( false );
  cin.tie( 0 );
  int n, m;
  while ( cin >> n >> m && n && m ) {
    VI p( n );
    for ( int i = 0; i < n; i++ ) {
      cin >> p[ i ];
    }
    p.push_back( 0 );
    SORT( p );
    set<int> two_selected;
    for ( int i = 0; i < n + 1; i++ ) {
      for ( int j = i; j < n + 1; j++ ) {
        two_selected.insert( p[ i ] + p[ j ] );
      }
    }
    int ans = 0;
    for ( set<int>::iterator it = two_selected.begin(); it != two_selected.end(); ++it ) {
      set<int>::iterator it2 = two_selected.upper_bound( m - *it );
      if ( it2 != two_selected.begin() ) {
        --it2;
        ans = max( ans, *it + *it2 );
      }
    }
    PRINT( ans );
  }
  return 0;
}