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//#pragma GCC optimize("Ofast")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#pragma warning(disable:4786)
#pragma warning(disable:4996)
#include <ctime>
#include<list>
#include <numeric>
#include<bitset>
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<set>
#include<map>
#include<functional>
#include<string>
#include<cstring>
#include<cstdlib>
#include<queue>
#include<utility>
#include<fstream>
#include<sstream>
#include<cmath>
#include<stack>
#include<assert.h>
#include<unordered_map>
#include<unordered_set>
#include <array>
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 rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
	~debug() { cerr << endl; }
	template<class c> typename enable_if<sizeof dud<c>(0) != 1, debug&>::type operator<<(c i) {
		cerr << boolalpha << i; return *this;
	}

	template<class c, int = 0> typename enable_if<sizeof dud<c>(0) == 1, debug&>::type operator<<(c i) {
		return *this << 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 (auto it = d.b; it != d.e; ++it)
			*this << ", " + 2 * (it == d.b) << *it;
		ris << "]";
	}
#else
	sim dor(const c&) { ris; }
#endif
};
#define watch(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

#define MEM(a, b) memset(a, (b), sizeof(a))
#define CLR(a) memset(a, 0, sizeof(a))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define ABS(X) ( (X) > 0 ? (X) : ( -(X) ) )
#define S(X) ( (X) * (X) )
#define SZ(V) (int )V.size()
#define FORN(i, n) for(int i = 0; i < n; i++)
#define FORAB(i, a, b) for(int i = a; i <= b; i++)
#define ALL(V) V.begin(), V.end()
#define IN(A, B, C)  ((B) <= (A) && (A) <= (C))
#define AIN(A, B, C) assert(IN(A, B, C))

//typedef int LL;
typedef long long int LL;
//typedef __int128 LLL;
typedef long long LLL;

typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef pair<double, double> PDD;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<PLL > VPL;
typedef vector<PII > VP;
typedef vector<double> VD;
typedef vector<vector<int>> VVI;
typedef vector<string> VS;
typedef long double ld;

#define MAXN 200005
const LL MOD = 998244353;
//const LL MOD = 998244353;
const LL INF = 2000000000000000001LL;

int n; LL m;
VL V;
VL sum;
LL dp[201][201][61][2];
char vis[201][201][61][2];
int mbits[100];

inline LL Sum(int l, int h) {
	if (l > h) return 0;
	LL r = sum[h];
	if (l > 0) r -= sum[l - 1];
	return r;
}

LL DP(int l, int h, int bit, int mode) {
	if (l == 0 && h == 3 && bit == 1 && mode == 0)
		l = l;

	if (l > h) return 0;
	if (bit == -1) {
		if (l == h) return 0;
		else return -INF;
	}

	if (h - l + 1 > (1LL << (bit + 1))) return -INF;
	LL& ret = dp[l][h][bit][mode];

	if (vis[l][h][bit][mode]) return ret;
	vis[l][h][bit][mode] = 1;

	ret = -INF;
	if (mode == 0) {
		for (int k = l - 1; k <= h; k++) {
			LL now = DP(l, k, bit - 1, 0) + DP(k + 1, h, bit - 1, 0) + Sum(k + 1, h);
			ret = MAX(ret, now);
		}
	}
	else {
		if (mbits[bit] == 0) {
			ret = DP(l, h, bit - 1, 1);
		}
		else {
			for (int k = l - 1; k <= h; k++) {
				LL now = DP(l, k, bit - 1, 0) + DP(k + 1, h, bit - 1, 1) + Sum(k + 1, h);
				ret = MAX(ret, now);
			}
		}
	}
	//printf("%d %d %d %d %lld\n", l, h, bit, mode, ret);
	return ret;
}

void solve(int ks) {
	LL temp = m;
	for (int i = 0; i < 100; i++) {
		mbits[i] = (temp & 1);
		temp >>= 1;
	}

	LL ans = DP(0, n - 1, 59, 1);
	printf("%lld\n", ans);
}

void input() {
	scanf("%d %lld", &n, &m);
	//n = 200;
	//m = 76657798978LL;
	V.clear();
	sum.clear();
	LL s = 0;
	FORN(i, n) {
		LL u;
		scanf("%lld", &u);
		//u = rand() * rand() * rand();
		//u = ABS(u);
		//if (rand() % 2) u *= -u;

		V.push_back(u);
		s += u;
		sum.push_back(s);
	}
}

int main()
{
	// double start_time = clock();
#ifdef LOCAL
	freopen("C:\\Home\\ContestCodes\\sample.in", "r", stdin);
	//	freopen("out.out", "w", stdout);
#endif

	if (0) {
		int T;
		scanf("%d", &T);
		//AIN(T, 1, 10);
		for (int ks = 1; ks <= T; ks++) {
			solve(ks);
			fprintf(stderr, "%d done\n", ks);
		}
	}
	else {
		input();
		solve(0);
	}


	// double end_time = clock();
	// fprintf(stderr, "Time = %lf\n", (end_time - start_time) / CLOCKS_PER_SEC);

	return 0;
}