#include <bits/stdc++.h>

using namespace std;

#define FOR(a, b, c) for(int a = (b); a < (c); a++)
#define PB push_back

using ll = long long;
#define LL long long

const int MAX = 2e5+7;
vector <int> arr;

int main() 
{
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int n, k;
    cin >> n >> k;

    arr.resize(n);
    FOR(i, 0, n)
    {
        cin >> arr[i];
    }

    int res = 0;

    for(int i = 30; i >= 0; --i)
    {
        vector <int> temp;

        FOR(j, 0, arr.size())
        {
            if(arr[j] & (1 << i))
            {
                temp.PB(arr[j]);
            }
        }

        if(temp.size() >= k)
        {
            res |= (1 << i);
            arr = temp;
        }
    }

    cout << res;
}