include[HTML_REMOVED]
include[HTML_REMOVED]
using namespace std;
define h 1000
int a[h];
int main()
{
int n,num,ans;
cin>>n;
for(int i=1;i<=n;i++)cin>>a[i];
num=a[3];
sort(a+1,a+n+1);
ans=num^a[1];
cout<<ans+2;
}