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#include <bits/stdc++.h>
using namespace std;

typedef long long int LL;
typedef unsigned long long int uLL;
typedef unsigned int uint;
typedef long double ld;


const int N = 207;
const LL INF = 2000000000000000000;
unordered_map <uLL, LL> dp[N];
int n, nr;
uLL m;
LL tab[N];

uLL bigger(uLL l, int ile){
    uLL p = 0;
    for(int i = 0; i < ile; i++){
        p |= (uLL(1)<<i);
    }
    int s = 0, t = ile;
    while(p < l){
        p <<= 1;
        s++;
        t++;
    }
    bool czy = false;
    while(t >= s){
        while(p >= l){
            if(s == 0){
                czy = true;
                break;
            }
            p |= (uLL(1)<<(s-1));
            p ^= (uLL(1)<<(t-1));
            s--;
            t--;
        }
        if(czy){
            break;
        }
        p ^= (uLL(1)<< s);
        p |= (uLL(1)<< t);
        s++;
    }
    return p;
}

LL rek(int pos, uLL mask){
    if(pos == n+1){
        return 0;
    }
    if(dp[pos].find(mask) != dp[pos].end()){
        return dp[pos][mask];
    }
    LL maks = -INF;
    if(mask == 0){
        maks = max(maks, rek(pos+1, 1));
    }
    for(int i = 1; i <= nr; i++){
        uLL zz = bigger(mask, i);
        if(zz > m){
            continue;
        }
        maks = max(maks, tab[pos]*i+rek(pos+1, zz+1));
    }
    dp[pos][mask] = maks;
    return maks;
}
int main(){
    cin.tie(NULL);
    ios_base::sync_with_stdio(0);
    cin >> n >> m;
    for(int i = 1; i <= n; i++){
        cin >> tab[i];
    }
    while((uLL(1)<<nr) < m) nr++;
    cout << rek(1, 0) << '\n';
    return 0;
}