#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <iomanip>
using namespace std;

typedef long long ll;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define per(i,a,b) for(ll i=(b-1);i>=(a);--i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(c) string(1,c)
#define print(x) cout<<#x<<" = "<<x<<endl;

#define MOD 1000000007

#define N 14
#define NH (N/2)

ll d[NH];
ll dd[N];
ll ddd[NH];

ll mx = 0;
vector<ll> v;

void fp(ll d[NH], ll dd[N], ll index){
  if(index==v.sz){
    clr(ddd,0);
    rep(i,0,v.sz){
      ddd[dd[i]]^=v[i];
    }
    ll sum = 0;
    rep(i,0,v.sz/2){
      sum += ddd[i];
    }
    mx = max(mx,sum);
    return;
  }
  rep(i,0,v.sz/2){
    if(d[i]==0){
      d[i]=1;
      dd[index]=i;
      fp(d,dd,index+1);
      d[i]=0;
      break;
    }
  }
  rep(i,0,v.sz/2){
    if(d[i]==1){
      d[i]=2;
      dd[index]=i;
      fp(d,dd,index+1);
      d[i]=1;
    }
  }
}

int main() {
  ll n;
  cin>>n;
  rep(i,0,n){
    ll a;
    cin>>a;
    v.pb(a);
  }
  ll index = 0;
  clr(d,0);
  clr(dd,0);
  fp(d,dd,index);
  cout << mx << endl;
  return 0;
}