#include<iostream>

using namespace std;

int n, niz[1000], naj;

int main(void)
{
    cin>>n;
    
    for ( int i = 0 ; i < n ; i ++ )
        cin>>niz[i];
        
    for ( int i = 0 ; i < n-1 ; i ++ )
        for ( int j = i + 1 ; j < n ; j ++ )
            {
              if ( niz[j] > niz[j-1] )
                   if ((niz[j]-niz[i])>naj)
                      naj= (niz[j]-niz[i]);
              else
                  break;       
                      
            }
    cout<<naj;

       
    return 0;                 
}