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#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;

long long a[200];
long long smallest_numbers[200][2];
long long biggest_sums[200][2];

long long limit_max_bits = 0;
int n;
long long m;

bool cmp(pair<long long, int> a_, pair<long long, int> b) {
    return a_.first < b.first;
}

long long getFirstNumberWithBits(long long number, int bits) {
    long long max_bits = floor(log2(number));
    long long current_bit = 1 << max_bits;
    int counted_bits = 0;
    long long result = 0;
    while (counted_bits < bits && current_bit > 0) {
        if (number & current_bit) {
            result += current_bit;
            counted_bits++;
        }
        current_bit >>= 1;
    }

    if (counted_bits == bits) {
        while ((result & 1) == 0) {
            result >>= 1;
        }
        result++;
        while (result <= number) {
            result <<= 1;
        }
        long long bit_counter = result;
        counted_bits = 0;
        while (bit_counter) {
            bit_counter &= (bit_counter - 1);
            counted_bits++;
        }
    }
    current_bit = 1;
    while (counted_bits < bits) {
        if ((result & current_bit) == 0) {
            result |= current_bit;
            counted_bits++;
        }
        current_bit <<= 1;
    }

    return result;
}

pair<long long, bool> getBestQuality(int index, long long current_sum, long long current_number) {
    if (index == n) {
        return pair<long long, bool>(current_sum, true);
    }

    if (current_number > m) {
        return pair<long long, bool>(0, false);
    }

    if (biggest_sums[index][0] >= current_sum && biggest_sums[index][1] <= current_number) {
        return pair<long long, bool>(0, false);
    }

    if (smallest_numbers[index][0] >= current_sum && smallest_numbers[index][1] <= current_number) {
        return pair<long long, bool>(0, false);
    }

    if (current_sum > biggest_sums[index][0]) {
        biggest_sums[index][0] = current_sum;
        biggest_sums[index][1] = current_number;
    }

    if (current_number < smallest_numbers[index][0]) {
        smallest_numbers[index][0] = current_sum;
        smallest_numbers[index][1] = current_number;
    }

    int i_start = 0;
    if (current_number != 0 || index != 0) {
        i_start = 1;
    }
    long long highest = 0;
    bool highest_set = false;

    pair<long long, int>* numbers = new pair<long long, int>[limit_max_bits + 1];

    for (int i = i_start; i <= limit_max_bits; i++) {
        long long number = 0;
        if (i != 0)
            number = getFirstNumberWithBits(current_number, i);
        numbers[i].first = number;
        numbers[i].second = i;
    }

    sort(numbers, numbers + limit_max_bits + 1, cmp);

    long long extreme = (a[index] > 0 ? -1000 : 1000);
    for (int i = i_start; i <= limit_max_bits; i++) {
        if (numbers[i].first > m)
            continue;
        if (a[index] > 0 && numbers[i].second <= extreme)
            continue;

        if (a[index] < 0 && numbers[i].second >= extreme)
            continue;

        if (a[index] == 0 && i > i_start)
            break;

        extreme = numbers[i].second;

        long long second_quality = a[index] * numbers[i].second;
        pair<long long, bool> result = getBestQuality(index + 1, current_sum + second_quality, numbers[i].first);
        if ((result.first > highest || !highest_set) && result.second) {
            highest = result.first;
            highest_set = true;
        }
    }
    delete [] numbers;
    return pair<long long, bool>(highest, highest_set);
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m;
    limit_max_bits = floor(log2(m)) + 1;


    for (int i = 0; i < 200; i++) {
        biggest_sums[i][0] = smallest_numbers[i][0] = -9223372036854775807LL;
        biggest_sums[i][1] = smallest_numbers[i][1] = 9223372036854775807LL;
    }

    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }

    cout << getBestQuality(0, 0, 0).first << "\n";


    return 0;
}