// C++ implementation of above approach 
#include <bits/stdc++.h> 
using namespace std; 

int max_profit(int a[],int b[],int n,int fee) 
{ 
    int i, j, profit; 
    int l, r, diff_day = 1, sum = 0; 
    b[0]=0;              
    b[1]=diff_day; 
    for(i=1;i<n;i++) 
    { 
    l=0; 
    r=diff_day; 
        sum=0;   

    for(j=n-1;j>=i;j--) 
    { 
        profit=(a[r]-a[l])-fee; 
        
        if(profit>0)     
        {   sum=sum+profit; } 
        l++; 
        r++; 
    } 
    if(b[0] < sum) 
    { 
        b[0] = sum; 
        b[1] = diff_day; 
    } 
    diff_day++; 
} 

return 0; 
} 
int main() 
{ 
    int n,i,j,k,m,q;
    cin>>n;
    int ar[n];
    rep(i,n)
        cin>>ar[i];
    int b[2]; 
    int tranFee = 0; 
    max_profit(arr, b, n, tranFee); 
    cout << b[0] << endl; 
    return 0; 
} 
