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#include <bits/stdc++.h>
using namespace std;
#define PII pair<int, int>
#define PLL pair<LL, LL>
#define VI vector<int>
#define VPII vector<PII>
#define LL long long
#define LD long double
#define f first
#define s second
#define MP make_pair
#define PB push_back
#define endl '\n'
#define ALL(c) (c).begin(), (c).end()
#define SIZ(c) (int)(c).size()
#define REP(i, n) for(int i = 0; i < (int)(n); ++i)
#define FOR(i, b, e) for(int i = (b); i <= (int)(e); ++i)
#define FORD(i, b, e) for(int i = (b); i >= (int)(e); --i)
#define sim template<class n
sim, class s> ostream & operator << (ostream &p, pair<n, s> x)
{return p << "<" << x.f << ", " << x.s << ">";}
sim> auto operator << (ostream &p, n y) ->
typename enable_if<!is_same<n, string>::value, decltype(y.begin(), p)>::type 
{int o = 0; p << "{"; for(auto c: y) {if(o++) p << ", "; p << c;} return p << "}";}
void dor() {cerr << endl;}
sim, class...s> void dor(n p, s...y) {cerr << p << " "; dor(y...);}
sim, class s> void mini(n &p, s y) {if(p>y) p = y;}
sim, class s> void maxi(n &p, s y) {if(p<y) p = y;}
#ifdef DEB
#define debug(...) dor(__FUNCTION__, ":", __LINE__, ": ", __VA_ARGS__)
#else
#define debug(...)
#endif 

#define I(x) #x " =", (x), " "
#define A(a, i) #a "[" #i " =", i, "] =", a[i], " "

// ******************************************************************************

#define bi(x) bitset<60>(x)
#define bity(x) __builtin_popcountll(x)
#define leading(x) (63-__builtin_clzll(x))

const int MXN = 205;
const LL INF = 4e18;

LL t[MXN];
LL pref[MXN];
LL sum(int a, int b)
  {
  return pref[b] - pref[a-1];
  }

bool done[65][2][MXN][MXN];
LL dp[65][2][MXN][MXN];
/*
Rozwiazuje zadanie na przedziale [a, b] wejściowego ciągu.
m oraz (ones, len) wzajemnie z siebie wynikają
*/
LL go(int a, int b, LL m, bool ones, int len)
  {
  if(a > b)return 0;
  if(a == b)
    {
    if(t[a] <= 0)return 0;
    return t[a] * leading(m+1);
    }
  if(m == 0)return -INF;

  if(done[len][ones][a][b])return dp[len][ones][a][b];
  done[len][ones][a][b] = 1;
  LL &res = dp[len][ones][a][b] = -INF;

  if(!(m & (1LL << len)))return res = go(a, b, m, ones, len-1);

  FOR(i, a, b+1)
    {  
    maxi(res, go(a, i-1, (1LL << len)-1, 1, len-1) +
              go(i, b, m - (1LL << len), ones, len-1) +
              sum(i, b));
    }

  return res;
  }


int main()
  {
  int n;
  LL m;
  cin >> n >> m; FOR(i, 1, n)cin >> t[i];
  FOR(i, 1, n)pref[i] = pref[i-1] + t[i];

  cout << go(1, n, m, 0, 60) << endl;
  }