#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXK = 105;

int k;
ll a[MAXK];
ll basis[65];  // 线性基

bool insert(ll x) {
    for (int i = 63; i >= 0; i--) {
        if (!(x >> i)) continue;
        if (!basis[i]) {
            basis[i] = x;
            return true;
        }
        x ^= basis[i];
    }
    return false;
}

int main() {
    scanf("%d", &k);
    ll sum = 0;
    for (int i = 0; i < k; i++) {
        scanf("%lld", &a[i]);
        sum += a[i];
    }
    
    // 从大到小排序
    sort(a, a + k, greater<ll>());
    
    ll ans = 0;
    for (int i = 0; i < k; i++) {
        if (!insert(a[i])) {
            ans += a[i];  // 不能插入线性基，即可以拿走
        }
    }
    
    printf("%lld\n", ans);
    return 0;
}