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#define make_pair mp
#define emplace_back pb
#include <bits/stdc++.h>
using namespace std;
const int N = 205, S = 60;
const long long INF = -2e18;
int n;
long long m[S], dp1[N][N][S], dp2[N][N][S], pref[N];
int main()
{
	scanf("%d%lld", &n, &m[S-1]);

	for(long long i=S-2;i>=0;i--) if(m[i+1] & (1LL<<(i+1LL))) m[i] = m[i+1] - (1LL<<(i+1LL));
	else m[i] = m[i+1];

	for(int i=1;i<=n;i++) {
		scanf("%lld", &pref[i]);
		pref[i] += pref[i-1];
	}

	for(int i=1;i<=n;i++)
	for(int j=i+2;j<=n;j++) dp1[i][j][0] = INF;

	for(int i=1;i<=n;i++) {
		dp1[i][i][0] = max(0LL, pref[i] - pref[i-1]);
		dp1[i][i+1][0] = pref[i+1] - pref[i]; 
	}

	for(int bit=1;bit<S;bit++)
	for(int d=0;d<n;d++)
	for(int p=1;p<=n-d;p++) {
		int k = p + d;
		dp1[p][k][bit] = INF;
		for(int l=p;l<=k+1;l++)
			dp1[p][k][bit] = max(dp1[p][k][bit], dp1[p][l-1][bit-1] + dp1[l][k][bit-1] + pref[k] - pref[l-1]);	

		//cout<<p<<" "<<k<<" "<<bit<<" "<<dp1[p][k][bit]<<endl;
	}

	for(int i=1;i<=n;i++)
	for(int j=i+2;j<=n;j++) dp2[i][j][0] = INF;

	for(int i=1;i<=n;i++) {
		dp2[i][i][0] = 0;
		if(m[0] % 2) dp2[i][i][0] = max(0LL, pref[i] - pref[i-1]);

		if(i != n) {
			if(m[0] % 2) dp2[i][i+1][0] = pref[i+1] - pref[i];
			else dp2[i][i+1][0] = INF;
		}
	}

	for(int bit=1;bit<S;bit++)
	for(int d=0;d<n;d++)
	for(int p=1;p<=n-d;p++) {
		int k = p + d;
		dp2[p][k][bit] = INF;
		long long xx = m[bit] & (1LL<<(long long)bit);
		if(!xx) {
			dp2[p][k][bit] = dp2[p][k][bit-1];
			//cout<<p<<" "<<k<<" "<<bit<<" "<<dp2[p][k][bit]<<endl;
		       	continue;
		}

		for(int l=p;l<=k+1;l++)
			dp2[p][k][bit] = max(dp2[p][k][bit], dp1[p][l-1][bit-1] + dp2[l][k][bit-1] + pref[k] - pref[l-1]);	

		//cout<<p<<" "<<k<<" "<<bit<<" "<<dp2[p][k][bit]<<endl;
	}

	printf("%lld\n", dp2[1][n][S-1]);
	return 0;
}