#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int n, k; cin >> n >> k;
  vector<int> a(n); REP(i, n) cin >> a[i];
  vector<ll> x, y;
  x.reserve(1 << (n / 2));
  REP(bit, 1 << (n / 2)) {
    x.emplace_back();
    REP(i, n / 2) {
      if (bit >> i & 1) x.back() += a[i];
    }
  }
  ranges::sort(x, greater<ll>());
  y.reserve(1 << ((n + 1) / 2));
  REP(bit, 1 << ((n + 1) / 2)) {
    y.emplace_back();
    REP(i, (n + 1) / 2) {
      if (bit >> i & 1) y.back() += a[i + n / 2];
    }
  }
  ranges::sort(y, greater<ll>());
  ll lb = min(ll{*ranges::min_element(a)}, 0LL) * n, ub = max(ll{*ranges::max_element(a)} * n, 0LL) + 1;
  while (ub - lb > 1) {
    const ll mid = midpoint(lb, ub);
    int num = 0, index = y.size() - 1;
    for (const ll x_i : x) {
      while (index >= 0 && x_i + y[index] < mid) --index;
      num += index + 1;
    }
    (num >= k ? lb : ub) = mid;
  }
  cout << lb << '\n';
  return 0;
}