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

typedef long long ll;
typedef pair<int, int> pii;

int main() {
    int n, k;
    scanf("%d %d", &n, &k);
    vector<int> mus(n);
    for (int i = 0; i < n; i++) scanf("%d", &mus[i]);
    
    int result = 0;
    for (int l = 29; l >= 0; l--) {
        vector<int> ones;
        for (int m : mus) {
            if (m & (1 << l)) ones.push_back(m);
        }
        if (ones.size() >= k) {
            result |= (1 << l);
            mus = ones;
        }
    }
    printf("%d\n", result);
    return 0;
}