#include<bits/stdc++.h>
#define rep(i,a,b) for(ll i=ll(a);i<ll(b);++i)
using namespace std;
typedef long long ll;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;
main(){
    int N;
    cin >> N;
    vector<ll> A(N);
    rep(i,0,N)cin >> A[i];
    ll ans = 0;
    rep(i,0,32){
        ll bit = 1 << i;
        rep(j,0,N){
            bit &= A[j];
        }
        ans += bit;
    }   
    ll maxi = 0;
    rep(i,0,N)maxi = max(maxi, ans ^ A[i]);
    cout << maxi << endl;
}