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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 mor > muu & operator << (
#define R22(r) sim > typename \
  enable_if<1 r sizeof dud<c>(0), muu&>::type operator<<(c g) {
sim > struct rge {c b, e; };
sim > rge<c> range(c h, c n) { return {h, n}; }
sim > auto dud(c * r) -> decltype(cerr << *r);
sim > char dud(...);
struct muu {
#ifdef LOCAL
stringstream a;
~muu() { cerr << a.str() << endl; }
R22(<) a << boolalpha << g; ris; }
R22(==) ris << range(begin(g), end(g)); }
sim, class b mor pair < b, c > r) { ris << "(" << r.first << ", " << r.second << ")"; }
sim mor rge<c> u) {
a << "[";
for (c i = u.b; i != u.e; ++i) 
  *this << ", " + 2 * (i == u.b) << *i;
 ris << "]";
 }
#else
sim mor const c&) { ris; }
#endif
muu & operator()() { ris; }
};
#define imie(r...) "[" #r ": " << (r) << "] "
#define debug (muu() << __FUNCTION__ << "#" << __LINE__ << ": ")

typedef long long ll;

const ll infll = 1e18 + 5;
ll m;

vector<ll> next_numbers(ll x) {
	int zap = __builtin_popcountll(x);
	int juzp = zap;
	int juzk = zap;
	vector<ll> res;
	res.push_back(x);
	ll y = x;
	for (int i = 0; i <= 61; i ++) {
		if (x & (1LL << i)) {
			y ^= (1LL << i);
		} else {
			y ^= (1LL << i);
			debug << imie(y) << juzp << " " << juzk;
			int z =  __builtin_popcountll(y);
			for (int j = z; j < juzp; j ++) {
				int b = j - z;
				res.push_back(y + (1LL << b) - 1);
				//~ assert( __builtin_popcountll(res.back()) == j);
			}
			
			for (int j = z + i; j > juzk; j --) {
				int b = j - z;
				res.push_back(y + (1LL << b) - 1);
				//~ assert( __builtin_popcountll(res.back()) == j);
			}
			
			juzp = min(juzp, z);
			juzk = max(juzk, z + i);
			
			y ^= (1LL << i);
		}
	}
	debug << res;
	
	//~ for (auto w : res) {
		//~ debug << __builtin_popcountll(w);
		//~ assert(w >= x);
	//~ }
	//~ for (auto w : res) {
		//~ for (auto v : res) {
			//~ if (w != v) {
				//~ assert(__builtin_popcountll(w) != __builtin_popcountll(v));
			//~ }
		//~ }
	//~ }
	return res;
}

void solve() {
	int n;
	cin >> n >> m;
	vector<ll> tab(n+1);
	for (int i= 1; i <= n; i ++) {
		cin >> tab[i];
	}
	// (end, res)
	vector<pair<ll, ll>> prev;
	vector<pair<ll, ll>> obc;
	debug << next_numbers(0);
	for (ll x : next_numbers(0)) {
		if (x <= m) prev.push_back({x + 1, tab[1] * __builtin_popcountll(x)});
	}
	debug << prev;
	for (int i = 2; i <= n; i ++) {
		obc.clear();
		for (auto p : prev) {
			ll e, res;
			tie(e, res) = p;
			for (ll x : next_numbers(e)) {
				if (x <= m) obc.push_back({x + 1, res + tab[i] * __builtin_popcountll(x)});
			}
		}
		sort(obc.begin(), obc.end());
		reverse(obc.begin(), obc.end());
		prev.clear();
		//~ debug << imie(tab[i]);
		//~ debug << cp;
		for (auto e : obc) {
			while (!prev.empty() && prev.back().second <= e.second) {
				prev.pop_back();
			}
			if (prev.empty() || prev.back().first > e.first) {
				prev.push_back(e);
			}
		}
		//~ debug << dp[i];
	}
	ll MAX = -infll;
	for (auto p : prev) {
		MAX = max(MAX, p.second);
	}
	cout << MAX << "\n";
}

int main() {
	ios_base::sync_with_stdio(0);
	solve();
}