#include <bits/stdc++.h>
#define whlie while
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define rep(i,N) for(int i = 0; i < (N); i++)
#define repr(i,N) for(int i = (N) - 1; i >= 0; i--)
#define rep1(i,N) for(int i = 1; i <= (N) ; i++)
#define repr1(i,N) for(int i = (N) ; i > 0 ; i--)
#define each(x,v) for(auto& x : v)
#define all(v) (v).begin(),(v).end()
#define sz(v) ((int)(v).size())
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
using namespace std; void solve();
using ll = long long; using vl = vector<ll>;
using vi = vector<int>; using vvi = vector< vector<int> >;
constexpr int inf = 1001001001;
constexpr ll infLL = (1LL << 61) - 1;
struct IoSetupNya {IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7);} } iosetupnya;
template<typename T, typename U> inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; }
template<typename T, typename U> inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; }
template<typename T, typename U> ostream& operator <<(ostream& os, const pair<T, U> &p) { os << p.first << " " << p.second; return os; }
template<typename T, typename U> istream& operator >>(istream& is, pair<T, U> &p) { is >> p.first >> p.second; return is; }
template<typename T> ostream& operator <<(ostream& os, const vector<T> &v) { int s = (int)v.size(); rep(i,s) os << (i ? " " : "") << v[i]; return os; }
template<typename T> istream& operator >>(istream& is, vector<T> &v) { for(auto &x : v) is >> x; return is; }
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
template<typename T>void die(T x){out(x); exit(0);}
#ifdef NyaanDebug
  #include "NyaanDebug.h"
  #define trc(...) do { cerr << #__VA_ARGS__ << " = "; dbg_out(__VA_ARGS__);} while(0)
  #define trca(v,N) do { cerr << #v << " = "; array_out(v , N);cout << endl;} while(0)
#else
  #define trc(...)
  #define trca(...)
  int main(){solve();}
#endif
using P = pair<int,int>; using vp = vector<P>;
constexpr int MOD = /**/ 1000000007; //*/ 998244353;
//////////
// 累積演算ライブラリ Accumulated Operation Library
template<typename T>
struct ACC{
  private:
    vector<T> Head,Tail;
    function<T(T,T)> f = [](T a,T b){return a + b;};
    function<T(T,T)> f_inv = [](T a,T b){return a - b;};
    T UNIT = 0;
  public:
    // Head[i]には[0 , i)の結果を代入する
    // Tail[i]には[i , N)の結果を代入する
    ACC(const vector<T> &v){
      int N = int(v.size());
      Head.resize(N + 1);
      Tail.resize(N + 1);
      Head[0] = Tail[N] = UNIT;
      for(int i = 0, j = N; i < N ; i++,j--){
        Head[i + 1] = f( Head[i] , v[i]);
        Tail[j - 1] = f( Tail[j] , v[j - 1]);
      }
    };
    // 半開区間[0 , k)の演算結果を返す
    T head(int k){ return Head[k]; }
    // 半開区間[k , N)の演算結果を返す
    T tail(int k){ return Tail[k]; }
    // 逆演算の存在するとき半開区間[l , r)の演算結果を返す
    T query(int l,int r){
      return f_inv(Head[r] , Head[l]);
    }
};

void solve(){
  inl(N , K);
  vl a(N); in(a);
  ACC<ll> ruiseki(a);

  vl v; v.reserve(N * (N + 1) / 2);
  rep(i , N){
    for(int j = i + 1 ; j <= N; j++) v.pb(ruiseki.query(i , j));
  }
  sort(all(v));
  trc(v);
  ll ans = 0;
  for(int bit = 42; bit >= 0; bit--){
    ll mask = 1LL << bit;
    vl w; w.reserve(N * (N + 1) / 2);
    int cnt = 0;
    each(x , v){
      if(x & mask) cnt++ , w.pb(x);
    }
    if(cnt >= K) {v.swap(w); ans += mask;}
  }
  out(ans);
}

Measured memory_bytes: 7164