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#ifndef LOCAL
#pragma GCC optimize ("O3")
#endif

#include <bits/stdc++.h>

using namespace std;

#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return {i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (c it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(x...) " [" #x ": " << (x) << "] "

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
template <typename A, typename B>
using unordered_map2 = __gnu_pbds::gp_hash_table<A, B>;
using namespace __gnu_pbds;
template <typename T> using ordered_set =
  __gnu_pbds::tree<T, __gnu_pbds::null_type, less<T>, __gnu_pbds::rb_tree_tag,
                   __gnu_pbds::tree_order_statistics_node_update>;
// ordered_set<int> s; s.insert(1); s.insert(2);
// s.order_of_key(1);    // Out: 0.
// *s.find_by_order(1);  // Out: 2.

using ld = long double;
using ll = long long;

constexpr int mod = 1000 * 1000 * 1000 + 7;
constexpr int odw2 = (mod + 1) / 2;

void OdejmijOd(int& a, int b) { a -= b; if (a < 0) a += mod; }
int Odejmij(int a, int b) { OdejmijOd(a, b); return a; }
void DodajDo(int& a, int b) { a += b; if (a >= mod) a -= mod; }
int Dodaj(int a, int b) { DodajDo(a, b); return a; }
int Mnoz(int a, int b) { return (ll) a * b % mod; }
void MnozDo(int& a, int b) { a = Mnoz(a, b); }
int Pot(int a, ll b) { int res = 1; while (b) { if (b % 2 == 1) MnozDo(res, a); a = Mnoz(a, a); b /= 2; } return res; }
int Odw(int a) { return Pot(a, mod - 2); }
void PodzielDo(int& a, int b) { MnozDo(a, Odw(b)); }
int Podziel(int a, int b) { return Mnoz(a, Odw(b)); }
int Moduluj(ll x) { x %= mod; if (x < 0) x += mod; return x; }

template <typename T> T Maxi(T& a, T b) { return a = max(a, b); }
template <typename T> T Mini(T& a, T b) { return a = min(a, b); }

constexpr ll inf = std::numeric_limits<ll>::max() / 3;

constexpr int nax = 205;
constexpr int bax = 61;

int n;
ll m;
ll suf[nax];
int len;
int bity[bax];

void LiczBity() {
  len = 0;
  while (m) {
    bity[len++] = m % 2;
    m /= 2;
  }
  assert(len < bax);
}

ll Suma(int a, int b) {
  return suf[a] - suf[b];
}

ll dp_full[bax][nax][nax];
ll dp_suf[bax][nax];

int main() {
  static_assert(nax * (ll(1e14) + 20) * (bax + 5) * 2 + 105 < inf);
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m;
  LiczBity();

  #ifdef LOCAL
  { debug deb;
    deb << "bity[" << len << "] =";
    for (int i = 0; i < len; i++) {
      deb << " " << bity[i];
    }
  }
  #endif

  for (int i = 0; i < n; i++) {
    cin >> suf[i];
  }
  for (int i = n - 1; i >= 0; i--) {
    suf[i] += suf[i + 1];
  }
  for (int p = 0; p < n; p++) {
    dp_full[0][p][p] = 0;
    dp_full[0][p][p + 1] = 0;
    for (int k = p + 2; k <= n; k++) {
      dp_full[0][p][k] = -inf;
    }
  }
  for (int b = 1; b < len; b++) {
    for (int p = 0; p < n; p++) {
      for (int k = p; k <= n; k++) {
        dp_full[b][p][k] = -inf;
        for (int s = p; s <= k; s++) {
          Maxi(dp_full[b][p][k],
               dp_full[b - 1][p][s] + dp_full[b - 1][s][k] + Suma(s, k));
        }
        debug() << "dp_full[" << b << "][" << p << "][" << k << "] = "
                << dp_full[b][p][k];
      }
    }
  }

  for (int p = 0; p <= n; p++) {
    dp_suf[0][p] = -inf;
  }
  dp_suf[0][n - 1] = 0;
  dp_suf[0][n] = 0;
  for (int b = 1; b <= len; b++) {
    if (bity[b - 1] == 0) {
      for (int p = 0; p <= n; p++) {
        dp_suf[b][p] = dp_suf[b - 1][p];
      }
    } else {
      for (int p = 0; p <= n; p++) {
        dp_suf[b][p] = -inf;
        for (int s = p; s <= n; s++) {
          Maxi(dp_suf[b][p],
               dp_full[b - 1][p][s] + dp_suf[b - 1][s] + Suma(s, n));
        }
      }
    }
  }

  cout << dp_suf[len][0] << endl;
  return 0;
}