#include <bits/stdc++.h>
//void converT
using namespace std;
int main()
{
//cout << __builtin_popcount(4) << endl;
int n;
int pomx;
long long m;
scanf("%d%lld", &n, &m);
int t[n];
long long mx = LLONG_MIN;
for(int i = 0; i < n; ++i){
scanf("%d", &t[i]);
}
int ile = 0;
for(int i = n-1; i <= m; ++i){
ile = 0;
int p = 0;
for(int j = n-1; j >=0; --j){
//cout<<t[j]<<" "<<j<<endl;
pomx = __builtin_popcount(i-p);
ile += t[j] * (pomx);
p++;
}
// cout<<ile<<endl;
if(mx < ile)
mx = ile;
}
//cout<<mx<<endl;
printf("%lld", mx);
return 0;
}