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

int main() {
  cin.tie(0);
  cin.sync_with_stdio(0);

  int n, k;
  cin >> n >> k;

  vector<int> a(n);
  for (auto& x : a) cin >> x;

  vector<ll> b;
  b.reserve(n * (n + 1) / 2);
  for (int i = 0; i < n; ++i) {
    ll sum = 0;
    for (int j = i; j < n; ++j) {
      sum += a[j];
      b.emplace_back(sum);
    }
  }

  // bits
  for (int bit = 39; bit >= 0; --bit) {
    auto pm = stable_partition(b.begin(), b.end(),
                               [bit](ll x) { return ((x >> bit) & 1); });
    int d = distance(b.begin(), pm);
    if (d >= k) b.resize(d);
  }

  ll ans = b[0];
  for (int i = 1; i < k; ++i) ans &= b[i];
  cout << ans;
}