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#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i=(a); i<(b); i++)
#define PPC(x) __builtin_popcountll((x))
#define ALL(x) (x).begin(), (x).end()
#define pb push_back
using namespace std;

const int maxN = 222, B = 60;
const long long INF = 3000000000000000000ll;

template <class T1, class T2> inline void remax(T1& a, T2 b)	{   a = max(a, (T1)b);  }

long long sum[maxN][maxN], dp[maxN][maxN][B+1], dpfit[maxN][maxN][B+1];

int main()
{
	int n;
	long long m;
	scanf ("%d%lld", &n, &m);
	FOR(i, 0, n)
		scanf ("%lld", &sum[i][i+1]);
	FOR(i, 0, n) FOR(j, i+2, n+1)
	{
		sum[i][j] = sum[i][j-1] + sum[j-1][j];
		dp[i][j][0] = dpfit[i][j][0] = -INF;
	}
	
	FOR(len, 1, n+1) FOR(i, 0, n+1-len) FOR(b, 1, B+1)
	{
		int j = i + len;
		bool bit = (1ll << b-1) & m;
		dp[i][j][b] = dp[i][j][b-1];
		dpfit[i][j][b] = bit ? dp[i][j][b-1] : dpfit[i][j][b-1];
		
		if (len > (1ll << b))
			continue;
		
		if (!bit)
			FOR(k, i, j)
				remax(dp[i][j][b], dp[i][k][b-1] + dp[k][j][b-1] + sum[k][j]);

		else FOR(k, i, j)
		{
			remax(dp[i][j][b], dp[i][k][b-1] + dp[k][j][b-1] + sum[k][j]);
			remax(dpfit[i][j][b], dp[i][k][b-1] + dpfit[k][j][b-1] + sum[k][j]);
		}
	}
	
	printf("%lld\n", dpfit[0][n][B]);
	return 0;
}