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#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define pb push_back
#define mp make_pair
#define all(a) begin(a),end(a)
#define FOR(x,val,to) for(int x=(val);x<int((to));++x)
#define FORE(x,val,to) for(auto x=(val);x<=(to);++x)
#define FORR(x,arr) for(auto &x: arr)
#define FORS(x,plus,arr) for(auto x = begin(arr)+(plus); x != end(arr); ++x)
#define FORREV(x,plus,arr) for(auto x = (arr).rbegin()+(plus); x !=(arr).rend(); ++x)
#define REE(s_) {cout<<s_<<'\n';exit(0);}
#define GET(arr) for(auto &i: (arr)) sc(i)
#define whatis(x) cerr << #x << " is " << (x) << endl;
#define e1 first
#define e2 second
#define INF 0x7f7f7f7f
typedef std::pair<int,int> pi;
typedef std::vector<int> vi;
typedef std::vector<std::string> vs;
typedef int64_t ll;
typedef uint64_t ull;
#define umap unordered_map
#define uset unordered_set
using namespace std;
using namespace __gnu_pbds;
 
#ifdef ONLINE_JUDGE
#define whatis(x) ;
#endif
#ifdef _WIN32
#define getchar_unlocked() _getchar_nolock()
#define _CRT_DISABLE_PERFCRIT_LOCKS
#endif
template<class L, class R> ostream& operator<<(ostream &os, map<L, R> P) { for(auto const &vv: P)os<<"("<<vv.first<<","<<vv.second<<")"; return os; }
template<class T> ostream& operator<<(ostream &os, set<T> V) { os<<"[";for(auto const &vv:V)os<<vv<<","; os<<"]"; return os; }
template<class T> ostream& operator<<(ostream &os, vector<T> V) { os<<"[";for(auto const &vv:V)os<<vv<<","; os<<"]"; return os; }
template<class L, class R> ostream& operator<<(ostream &os, pair<L, R> P) { os<<"("<<P.first<<","<<P.second<<")"; return os; }
inline int fstoi(const string &str){auto it=str.begin();bool neg=0;int num=0;if(*it=='-')neg=1;else num=*it-'0';++it;while(it<str.end()) num=num*10+(*it++-'0');if(neg)num*=-1;return num;}
inline void getch(char &x){while(x = getchar_unlocked(), x < 33){;}}
inline void getstr(string &str){str.clear(); char cur;while(cur=getchar_unlocked(),cur<33){;}while(cur>32){str+=cur;cur=getchar_unlocked();}}
template<typename T> inline bool sc(T &num){ bool neg=0; int c; num=0; while(c=getchar_unlocked(),c<33){if(c == EOF) return false;} if(c=='-'){ neg=1; c=getchar_unlocked(); } for(;c>47;c=getchar_unlocked()) num=num*10+c-48; if(neg) num*=-1; return true;}template<typename T, typename ...Args> inline void sc(T &num, Args &...args){ bool neg=0; int c; num=0; while(c=getchar_unlocked(),c<33){;} if(c=='-'){ neg=1; c=getchar_unlocked(); } for(;c>47;c=getchar_unlocked()) num=num*10+c-48; if(neg) num*=-1; sc(args...); }
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; //s.find_by_order(), s.order_of_key() <- works like lower_bound
template<typename T> using ordered_map = tree<T, int, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define N 1000001
static uint16_t wordbits[65536] = { /* bitcounts of integers 0 through 65535, inclusive */ };
//This algorithm uses 3 arithmetic operations and 2 memory reads.
int popcount32e(uint32_t x){
    return wordbits[x & 0xFFFF] + wordbits[x >> 16];
}

//Optionally, the wordbits[] table could be filled using this function
void popcount32e_init(){
    uint32_t i;
    uint16_t x;
    int count;
    for(i=0; i <= 0xFFFF; i++){
        x = i;
        for(count=0; x; count++) // borrowed from popcount64d() above
            x &= x - 1;
        wordbits[i] = count;
    }
}

int popcount64d(uint64_t x){
    return popcount32e(x >> 32) + popcount32e(x & (((ll)1 << (32)) - 1 ));
}

#define popcnt(x) popcount64d(x)

//k = 0 jest specjalne
/* map<<ll,int>> memo; */
ll bestx(ll x, int k){ //min n that n > x, popcnt(n) == k
	++x;
    /* int pop = popcnt(x); */
    /* if(pop > k){ */
    /*     do{ */
    /*         x |= x-1; */
    /*         ++x; */
    /*     }while(popcnt(x) > k); */
    /* } */
    /* else{ */
    /*     for(int i = k-pop; i != 0; --i) { */
    /*         x |= x+1; */
    /*     } */
    /* } */
    int pop = popcnt(x);
    if(pop > k){
        /* for(int i = pop - k - 1; i != 0; --i){ */
        x |= x-1;
            /* x ^= (ll)1 << (__builtin_ffsll(x)-1); */
        ++x;
        /* } */
        /* x += (ll)1 << (__builtin_ffsll(x)-1); */
        while(popcnt(x) > k){
            x |= x-1;
            ++x;
        }
    }
    for(int i = k - popcnt(x); i != 0; --i) {
        x |= x+1;
    }
    /* assert(popcnt(x) == k); */
    return x;
}
 
int main(){
    popcount32e_init();
    /* whatis(bestx(6,2)) */
    ios_base::sync_with_stdio(0);cin.tie(0);
    ll n,lim;
    sc(n,lim);
    ll a[n];
    GET(a);
    map<ll,ll> st; //[x] -> ans
    st[-1] = 0;
    bool isf = 1;
    FORR(i,a){
        map<ll,ll> st2;
        if(isf){
            isf = 0;
            st2[0] = 0;
        }
        if(i <= 0){
            for(auto it = st.begin(); it != st.end(); ++it){
                ll lm = min(lim,(ll)(next(it) == st.end()?LONG_LONG_MAX:next(it)->e1));
                ll mn = LONG_LONG_MAX;
                for(int k = 1; k < 61; ++k){ //k < 61
                    ll wh = bestx(it->e1,k);
                    if(wh > lm) continue;
                    if(mn <= wh) continue;
                    mn = wh;
                    ll newv = it->e2 + i * k;
                    auto ret = st2.insert({wh,newv});
                    auto it = ret.e1;
                    if(ret.e2){
                        if(it != st2.begin() && it->e2 <= prev(it)->e2)
                            st2.erase(it);
                        else{
                            while(next(it) != st2.end() && next(it)->e2 <= it->e2)
                                st2.erase(next(it));
                        }
                    }
                    else{
                        if(it->e2 < newv){
                            it->e2 = newv;
                            while(next(it) != st2.end() && next(it)->e2 <= it->e2)
                                st2.erase(next(it));
                        }
                    }
                }
            }
        }
        else{
            for(auto it = st.begin(); it != st.end(); ++it){
                ll lm = min(lim,(ll)(next(it) == st.end()?LONG_LONG_MAX:next(it)->e1));
                ll mn = LONG_LONG_MAX;
                for(int k = 60; k > 0; --k){ //k < 61
                    ll wh = bestx(it->e1,k);
                    if(wh > lm) continue;
                    if(mn <= wh) continue;
                    mn = wh;
                    ll newv = it->e2 + i * k;
                    auto ret = st2.insert({wh,newv});
                    auto it = ret.e1;
                    if(ret.e2){
                        if(it != st2.begin() && it->e2 <= prev(it)->e2)
                            st2.erase(it);
                        else{
                            while(next(it) != st2.end() && next(it)->e2 <= it->e2)
                                st2.erase(next(it));
                        }
                    }
                    else{
                        if(it->e2 < newv){
                            it->e2 = newv;
                            while(next(it) != st2.end() && next(it)->e2 <= it->e2)
                                st2.erase(next(it));
                        }
                    }
                }
            }
        }
        st.swap(st2);
        /* for(auto it = st.begin(); it != st.end(); ++it){ */
        /*     while(next(it) != st.end() && next(it)->e2 <= it->e2) */
        /*         st.erase(next(it)); */
        /* } */
        /* whatis(st.size()) */
    }
    /* whatis(st.size()) */
    ll ans = LONG_LONG_MIN;
    FORR(i,st)
        ans = max(ans,i.e2);
    cout << ans << '\n';
}//