#include<cstdio>
typedef long long ll;
const int N=67,M=205;
const ll inf=3000000000000000000LL;
int n,len,i,b[N];ll m,a[M],s[M],f[N][2][M][M];bool v[N][2][M][M];
inline void up(ll&a,ll b){a<b?(a=b):0;}
ll dfs(int x,int y,int l,int r){
  if(l>r)return 0;
  if(!x)return l==r?0:-inf;
  if(v[x][y][l][r])return f[x][y][l][r];
  v[x][y][l][r]=1;
  ll tmp=-inf;
  int ny=y;
  if(y==1&&b[x]==1)ny=0;
  up(tmp,dfs(x-1,ny,l,r));
  if(y==0||b[x]==1)for(int i=l;i<=r;i++)up(tmp,dfs(x-1,ny,l,i-1)+dfs(x-1,y,i,r)+s[r]-s[i-1]);
  return f[x][y][l][r]=tmp;
}
int main(){
  scanf("%d%lld",&n,&m);
  if(!m)return puts("0"),0;
  while(m)b[++len]=m&1,m>>=1;
  for(i=1;i<=n;i++)scanf("%lld",&a[i]),s[i]=s[i-1]+a[i];
  printf("%lld",dfs(len,1,1,n));
}