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

typedef long long ll;
typedef double lf;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

#define TRACE(x) cerr << #x << ' ' << x << endl
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) FOR(i, 0, n)
#define _ << ' ' <<

#define fi first
#define sec second
#define se second
#define mp make_pair
#define pb push_back

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

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

  int sol = 0;

  for (int i = 31; i >= 0; i--) {
    int cnt = 0;
    for (int x : a) if ((1 << i) & x) cnt++;
    if (cnt >= k) {
      vector<int> tmp;
      for (int x : a) if ((1 << i) & x) tmp.push_back(x);
      a = tmp;
      sol +=  (1 << i);
    }
  }

  cout << sol;


  return 0;
}