#include <bits/stdc++.h>

using namespace std;

#define rint register int

#define IL inline

#define rep(i,h,t) for (rint i=h;i<=t;i++)

#define dep(i,t,h) for (rint i=t;i>=h;i--)

const int N=2e5;

int a[N];

bool t[];

vector<int> ve[];

bool f[][];

int main()

{

  freopen("1.in","r",stdin);

  freopen("1.out","w",stdout);

  ios::sync_with_stdio(false);

  int n,k;

  cin>>n>>k; k=n-k;

  rep(i,,n) cin>>a[i];

  if (k>=)

  {

    rep(i,,n)

      dep(j,,) t[j]|=(a[i]>>j)&;

    int ans=;

    rep(i,,)

      if (t[i]) ans+=<<i;

    cout<<ans<<endl;

    exit();

  }

  f[][]=;

  rep(i,,k-)

    rep(j,,(<<)-)

      if (f[i][j])

        rep(l,,n)

          f[i+][j|a[l]]=;

  dep(j,(<<)-,)

    if (f[k][j])

    {

      cout<<j<<endl;

      exit();

    }

  return ;

}