#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

#include<bitset>

#define maxn 2000050

using namespace std;

bitset <maxn> bit;

int n,x,ans=,sum=;

int main()

{

    scanf("%d",&n);bit[]=;

    for (int i=;i<=n;i++)

    {

        scanf("%d",&x);

        sum+=x;bit^=(bit<<x);

    }

    for (int i=;i<=sum;i++)

        if (bit[i]) ans^=i;

    printf("%d\n",ans);

    return ;

}