Given a set of integers S = { a1, a2, a3, ... a|S| }, we define a function X on S as follows:
X( S ) = a1 ^ a2 ^ a3 ^ ... ^ a|S|.
(^ stands for bitwise ‘XOR‘ or ‘exclusive or‘)

Given a set of N integers, compute the maximum of the X-function over all the subsets of the given starting set.

Input

The first line of input contains a single integer N, 1 <= N <= 105.
Each of the next N lines contain an integer ai, 1 <= ai <= 1018.

Output

To the first line of output print the solution.

Example

Input:

3
1
2
4
Output:

7

/* ***********************************************Author        :guanjunCreated Time  :2016/9/8 15:30:01File Name     :spoj_XMAX.cpp************************************************ */#include <iostream>#include <cstring>#include <cstdlib>#include <stdio.h>#include <algorithm>#include <vector>#include <queue>#include <set>#include <map>#include <string>#include <math.h>#include <stdlib.h>#include <iomanip>#include <list>#include <deque>#include <stack>#define ull unsigned long long#define ll long long#define mod 90001#define INF 0x3f3f3f3f#define maxn 100010#define cle(a) memset(a,0,sizeof(a))const ull inf = 1LL << 61;const double eps=1e-5;using namespace std;priority_queue<int,vector<int>,greater<int> >pq;struct Node{    int x,y;};struct cmp{    bool operator()(Node a,Node b){        if(a.x==b.x) return a.y> b.y;        return a.x>b.x;    }};bool cmp(ll a,ll b){    return a>b;}ll a[maxn];int main(){    #ifndef ONLINE_JUDGE    freopen("in.txt","r",stdin);    #endif    //freopen("out.txt","w",stdout);    int n;    while(cin>>n){        for(int i=1;i<=n;i++)cin>>a[i];        sort(a+1,a+1+n,cmp);        int row=1;        for(int i=60;i>=0;i--){            for(int j=row;j<=n;j++){                if(a[j]&(1LL<<i)){                    swap(a[row],a[j]);                    for(int k=1;k<=n;k++){                        if((a[k]&(1LL<<i))&&(k!=row)){                            a[k]=a[k]^a[row];                        }                        //puts("YES");                    }                    row++;                }            }        }        ll ans=0LL;        for(int i=1;i<=n;i++){        //    cout<<a[i]<<endl;            ans^=a[i];        }        cout<<ans<<endl;    }    return 0;}