// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
#define rep(i,n) for (ll i = 0; i < (n); ++i)
using vl = vector<ll>;
using vvl = vector<vl>;
using P = pair<ll,ll>;
#define pb push_back
#define int long long
#define double long double
#define INF (ll) 3e18
// Ctrl + Shift + B コンパイル
// Ctrl + C 中断
// ./m 実行


signed main(){
  int n, k;
  cin >> n >> k;
  vl a(n);
  rep(i,n) cin >> a[i];
  vl b = {0};
  vl c = {0};
  rep(i, n/2){
    vl newb = b;
    for(auto x : b) newb.push_back(x+a[i]);
    b = newb;
  }
  for(int i = n/2; i<n; i++){
    vl newc = c;
    for(auto x : c) newc.push_back(x+a[i]);
    c = newc;
  }
  sort(b.begin(), b.end());
  sort(c.begin(), c.end());
  // for(auto x : b) cout << x << " "; cout << endl;
  // for(auto x : c) cout << x << " "; cout << endl;
  int ok = -INF; int ng = INF;
  while(ng - ok != 1){
    int mid = (ok + ng) / 2;
    // mid以上がk個以上あるか
    int count = 0;
    for(auto x : b){
      int y = mid - x;
      count += c.end() - lower_bound(c.begin(),c.end(),y);
    }
    // cout << mid << " " << count << endl;
    if (count >= k) ok = mid;
    else ng = mid;
  }
  cout << ok << endl;
}