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

import (
	"fmt"
	"sort"
)

func max(n, m int64) int64 {
	if n < m {
		return m
	} else {
		return n
	}
}

func main() {
	for {
		var N int
		var M int64
		fmt.Scan(&N, &M)
		if N == 0 && M == 0 {
			break
		}

		arr := make([]int64, N+1)
		for i := 1; i <= N; i++ {
			fmt.Scan(&arr[i])
		}
		sort.Slice(arr, func(i, j int) bool { return arr[i] < arr[j] })

		sums := make([]int64, len(arr)*len(arr))
		for i := 0; i < len(arr); i++ {
			for j := 0; j < len(arr); j++ {
				sums[i*len(arr)+j] = arr[i] + arr[j]
			}
		}

		sort.Slice(sums, func(i, j int) bool { return sums[i] < sums[j] })
		var m int64 = 0
		for _, val := range sums {
			rem := M - val
			if rem >= 0 {
				index := sort.Search(len(sums), func(i int) bool { return sums[i] > rem }) - 1
				if index >= 0 {
					m = max(m, val+sums[index])
				}
			}
		}
		fmt.Println(m)
	}
}

C++: #include <iostream>
#include <vector>
#include <set>
#include <map>
#include <sstream>
#include <string>
#include <cstdio>
#include <stack>
#include <queue>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cstring>
#include <tuple>
#include <utility>
#include <list>
#include <cmath>

using namespace std;

typedef long long LL;
typedef vector<int> Array;
typedef pair<int, int> P;

const LL LINF = 1LL << 60;
const LL MOD = 100000;
#define rep(i,n) for(int i=0;i<(int)n;++i)
#define all(c) (c).begin(), (c).end()

struct edge{ LL to, cost; edge(int t, LL c) :to(t), cost(c){} };

int dxk[] = { 1, 1, 1, 0, -1, 0 };
int dxg[] = { 0, 1, 0, -1, -1, -1 };
int dy[] = { -1, 0, 1, 1, 0, -1 };

int main()
{
	int n;
	LL m;
	while (cin >> n >> m && n)
	{
		vector<LL> nums(n);
		rep(i, n) cin >> nums[i];
		vector<LL> arr(n*n + 2);
		rep(i, n) rep(j, n)
		{
			arr[i * n + j] = nums[i] + nums[j];
		}
		rep(i, n) arr[n*n + 1] = nums[i];
		sort(all(arr));

		LL ans = 0;
		for (auto x : arr)
		{
			LL rem = m - x;
			auto it = upper_bound(all(arr), rem);
			if (it != arr.begin())
			{
				LL num = *(--it);
				ans = max(ans, num + x);
			}
		}
		cout << ans << endl;
	}
	return 0;
}

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

int m, n, p[1000], pp[1000*1000];

int main(){
    while( true ){
        cin >> n >> m;
        if( m == 0 && n == 0 ) break;
        for(int i = 0; i < n; i++){
            cin >> p[i];
        }
        sort(p, p+n);
        for(int i = 0; i < n*n; i++){
            pp[i] = p[i/n] + p[i%n];
        }
        sort(pp, pp + n*n);
        int c = n/p[n-1];
        if( c >= 4 ){
            cout << p[n-1]*4;
            continue;
        }
        int cand = 0;
        if( c <= 3 ){
            int j = n*n-1;
            for(int i = 0; i <= n*n/2; i++){
                while( pp[i] + pp[j] > m ) j--;
                cand = max(cand, pp[i] + pp[j]);
            }
        }
        if( c <= 2 ){
            int j = n*n-1;
            for(int i = 0; i <= n/2; i++){
                while( p[i] + pp[j] > m) j--;
                cand = max(cand, p[i] + pp[j]);
            }
        }
        if( c <= 1 ){
            int j = n-1;
            for(int i = 0; i <= n/2; i++){
                while( p[i] + p[j] > m ) j--;
                cand = max(cand, p[i] + p[j]);
            }
        }
        int k;
        for(k = n-1; p[k] > m && k > 0; k--);
        cand = max(cand, p[k]);
        cout << cand << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define for_(i,a,b) for(int i=(a);i<(b);++i)

int main() {
	int N, M;
	
	while (cin >> N >> M, N) {
		vector< int > P(N);
		for_(i,0,N) cin >> P[i];
		
		sort(P.begin(), P.end(), greater< int >());
		
		int cnt = 0, ans = 0;
		for_(i,0,N) {
			while (ans + P[i] <= M) ans += P[i], ++cnt;
			if (cnt == 4) break;
		}
		cout << ans << endl;
	}
}

C++: #include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
//#include <utility>
#include <set>
#include <iostream>
//#include <memory>
#include <string>
#include <vector>
#include <algorithm>
//#include <functional>
#include <sstream>
//#include <deque>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
//#include <cctype>
#include <cstring>
//#include <ctime>
#include <iterator>
#include <bitset>
//#include <numeric>
//#include <list>
//#include <iomanip>

#if __cplusplus >= 201103L
#include <array>
#include <tuple>
#include <initializer_list>
#include <unordered_set>
#include <unordered_map>
#include <forward_list>

#define cauto const auto&
#else

#endif

using namespace std;


namespace{
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll, vLL;
typedef vector<vector<long long> > vvll, vvLL;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
    v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
    stringstream ss;
    ss << f;
    ss >> t;
}


#define reep(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) reep((i),0,(n))
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define F first
#define S second
#define mkp make_pair
#define RALL(v) (v).rbegin(),(v).rend()


#define MOD 1000000007LL
#define EPS 1e-8
static const int INF=1<<24;

void mainmain(){
	int n,m;
	while(cin>>n>>m,n||m){
		vint v(n);
		rep(i,n){
			cin>>v[i];
		}
		v.PB(0);
		set<int> se;
		rep(i,n+1){
			rep(j,n+1){
				se.insert(v[i]+v[j]);
			}
		}
		// se.insert(0);
		int ans=0;
		for(auto i:se){
			if(i>m) break;
			auto it=se.upper_bound(m-i);
			it--;
			ans=max(ans,i+*it);
		}
		cout<<ans<<endl;
	}
}



}
main() try{
    mainmain();
}
catch(...){
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int p[1001],s[1002001];
int main(){
	int n,m;
	while(true){
	cin>>n>>m;
	if(n==0&&m==0)break;
	int cnt=1;
	p[0]=0,s[0]=0;
	for(int i=1;i<=n;i++){
		cin>>p[i];
		for(int j=0;j<=i;j++)
			s[cnt]=p[i]+p[j],cnt++;
	}
	sort(s,s+cnt);
	int ans=0;
	for(int i=0;i<cnt;i++){
		int left=0,right=cnt,mid;
		while(true){
			if(left>=right-1){
				mid=(left+right)/2;
			    if(s[i]+s[mid]<=m)
				ans=max(ans,s[i]+s[mid]);
				break;
			}
			mid=(left+right)/2;
			if(s[i]+s[mid]<=m){
				ans=max(ans,s[i]+s[mid]);
				left=mid;
			}
			else right=mid;
		}
	}
	cout<<ans<<endl;
	}
	return 0;
}