#include <iostream>
using namespace std;
int Maxsum(int left,int right,int a[])
{
    if(left==right)   //只有一个元素时
        return a[left];
    if(left==right-1)   //只有两个元素时
        return a[left]>a[right]?a[left]:a[right];
    else
    {
        int mid=(left+right)/2;
        return Maxsum(left,mid,a)>Maxsum(mid+1,right,a)?Maxsum(left,mid,a):Maxsum(mid+1,right,a);
    }
}
int main()
{
   int n;
   cin>>n;
   int a[n];
   for(int i=0;i<n;i++)
       cin>>a[i];
   cout<<Maxsum(0,n,a)<<endl;
   return 0;
}