#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using namespace atcoder;

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<ld> vd;
typedef vector<vd> vvd;
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<string> vs;
typedef vector<vs> vvs;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef modint998244353 mint; // atcoder
typedef vector<mint> vm; // atcoder
typedef vector<vm> vvm; // atcoder
template<class T> using pqmax = priority_queue<T, vector<T>, less<T>>; // 昇順
template<class T> using pqmin = priority_queue<T, vector<T>, greater<T>>; // 降順

#define overload4(_1,_2,_3,_4,name,...) name
#define REP1(n) for(ll i=0;i<n;i++)
#define REP2(i,n) for(ll i=0;i<n;i++)
#define REP3(i,a,b) for(ll i=a;i<b;i++)
#define REP4(i,a,b,c) for(ll i=a;i<b;i+=c)
// 1: 0->n-1, 2: i,0->n-1, 3: i,a->b-1, 4: i,a->b-1,c
#define REP(...) overload4(__VA_ARGS__, REP4, REP3, REP2, REP1)(__VA_ARGS__)
#define RREP1(n) for(ll i=n;i>0;i--)
#define RREP2(i,n) for(ll i=n;i>0;i--)
#define RREP3(i,a,b) for(ll i=a;i>b;i--)
#define RREP4(i,a,b,c) for(ll i=a;i>b;i-=c)
// 1: n->1, 2: i,n->1, 3: i,a->b+1, 4: i,a->b+1,c
#define RREP(...) overload4(__VA_ARGS__, RREP4, RREP3, RREP2, RREP1)(__VA_ARGS__)
#define REPA(i, a) for(auto&&i:a)
#define ALL(x) x.begin(), x.end()
#define SZ(x) (int)x.size()

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
template<class... T>constexpr auto min(T... a){ return min(initializer_list<common_type_t<T...>>{a...}); }
template<class... T>constexpr auto max(T... a){ return max(initializer_list<common_type_t<T...>>{a...}); }

template<class... T>void input(T&... a){ (cin >> ... >> a); }
void print(){ cout << '\n'; }
template<class T, class... Ts>void print(const T& a, const Ts&... b){ cout << a; (cout << ... << (cout << ' ', b)); cout << '\n'; }

constexpr int MOD = 998244353;
constexpr int inf = 1001001001;
constexpr ll INF = 1001001001001001001;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(20);

    bitset<4000001> bs;
    bs[0] = 1;
    int N;
    cin >> N;
    REP(N){
        int a;
        cin >> a;
        bs ^= (bs << a);
    }
    int ans = 0;
    REP(i, 4000001){
        if (bs[i]){
            ans ^= i;
        }
    }
    cout << ans << endl;
    return 0;
}