/* -*- coding: utf-8 -*-
 *
 * 2370.cc:  No.2370 He ate many cakes - yukicoder
 */

#include<cstdio>
#include<set>
#include<unordered_set>
#include<algorithm>
#include<utility>
 
using namespace std;

/* constant */

const int MAX_N = 30;
const int NBITS = 1 << MAX_N;

/* typedef */

using ll = long long;
using pli = pair<ll,int>;
using spli = set<pli>;
using usi = unordered_set<int>;

/* global variables */

int as[MAX_N];

/* subroutines */

/* main */

int main() {
  int n, k;
  scanf("%d%d", &n, &k);
  for (int i = 0; i < n; i++) scanf("%d", as + i);

  int nbits = 1 << n, bits0 = 0;
  ll sum0 = 0;
  for (int i = 0; i < n; i++)
    if (as[i] >= 0) {
      bits0 |= (1 << i);
      sum0 += as[i];
    }

  spli q;
  q.insert({sum0, bits0});
  usi used;
  used.insert(bits0);
  
  int c = 0;
  ll sumk = 0;
  while (c < k && ! q.empty()) {
    auto sit = q.end(); sit--;
    auto [s, bits] = *sit; q.erase(sit);
    if (++c >= k) { sumk = s; break; }

    for (int i = 0, bi = 1; i < n; i++, bi <<= 1)
      if (used.find(bits ^ bi) == used.end()) {
	ll sum1 = s + ((bits & bi) ? -as[i] : as[i]);
	int bits1 = bits ^ bi;
	q.insert({sum1, bits1});
	used.insert(bits1);
      }
    
    while (q.size() > k - c) q.erase(q.begin());
  }

  printf("%lld\n", sumk);
  
  return 0;
}