#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cassert>
#include<cmath>
#include<ctime>
#include<iomanip>
#include<numeric>
#include<stack>
#include<queue>
#include<map>
#include<unordered_map>
#include<set>
#include<unordered_set>
#include<bitset>
#include<random>
using namespace std;
int N,K,A[30];
void solve()
{
	cin >> N >> K;
	for(int i = 0;i < N;i++) cin >> A[i];
	vector<long long> D,U;
	for(int i = 0;i < 1 << N/2;i++) 
	{
		long long s = 0;
		for(int j = 0;j < N/2;j++) if(i >> j & 1) s += A[j];
		D.push_back(s);
	}
	for(int i = 0;i < 1 << N-N/2;i++)
	{
		long long s = 0;
		for(int j = 0;j < N-N/2;j++) if(i >> j & 1) s += A[j+N/2];
		U.push_back(s);
	}
	sort(D.begin(),D.end(),greater<long long>());
	sort(U.begin(),U.end());
	long long ok = -2e18,ng = 2e18;
	while(ng-ok > 1)
	{
		long long mid = (ok+ng)/2;
		long long cnt = 0;
		int id = 0;
		for(int i = 0;i < (int)D.size();i++)
		{
			while(id < (int)U.size() && D[i]+U[id] < mid) id++;
			cnt += (int)U.size()-id;
		}

		if(cnt >= K) ok = mid;
		else ng = mid;
	}

	cout << ok << endl;
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int tt = 1;
	//cin >> tt;
	while(tt--) solve();
}