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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, n1, n2, k;
    cin >> n >> k;
    n1 = n / 2, n2 = n - n1;
    vector<ll> a(n1), b(n2), a2(1 << n1), b2(1 << n2);
    for(auto &&v : a) cin >> v;
    for(auto &&v : b) cin >> v;
    for(int i = 0; i < (1 << n1); i++){
        for(int j = 0; j < n1; j++){
            if(i >> j & 1) a2[i] += a[j];
        }
    }
    for(int i = 0; i < (1 << n2); i++){
        for(int j = 0; j < n2; j++){
            if(i >> j & 1) b2[i] += b[j];
        }
    }
    sort(a2.begin(), a2.end());
    sort(b2.rbegin(), b2.rend());
    auto f = [&](ll v){
        int ans = 0;
        for(int i = 0, j = 0; i < a2.size() && ans < k; i++){
            while(j < b2.size() && a2[i] + b2[j] >= v) j++;
            ans += j;
        }
        return ans;
    };
    ll ok = -(1ll << 30) * n, ng = -ok, mid;
    while(ok + 1 < ng){
        mid = (ok + ng) / 2;
        (f(mid) >= k ? ok : ng) = mid;
    }
    cout << ok << '\n';
}