#include<bits/stdc++.h>
using namespace  std;
using ll = long long;
 
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
 
        ll n, k; cin >> n >> k;
        vector<ll> v(n);
        ll sum = 0;
        for(int i = 0; i < n; i++) {
            cin >> v[i];
            sum += v[i];
        }

        vector<ll> ans;

        for(int i = 0; i < 62; i++) {
            ll cnt = 0;
            for(int j = 0; j < n; j++) {
                if((v[j] & (1 << i))) {
                    cnt++;
                }
            }

            if(cnt&1) {
                ans.push_back(1);
            }else {
                ans.push_back(0);
            }
        }

        ll sum2 = 0;

    for(int i = 0; i < ans.size(); i++) {
        if(ans[i] == 1) {
            sum2 += (1LL << i);
        }  
    }

    while(sum2 > k) {
        sum2 = (sum2 >> 1);
    }

    cout << sum + sum2 << '\n';

    
    return 0;
}