#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>

using namespace std;

int n, p[1010], mx, beg, last, t;
bool up;

int main(){
    scanf( "%d", &n );
    p[n] = -1;
    for( int i = 0; i < n; ++i ) scanf( "%d", &p[i] );
    for( int i = 1; i <= n; ++i ){
        if( p[i] > p[i-1] && !up ) { up = 1; beg = p[i-1]; }
        else if( p[i] <= p[i-1] && up ){ up = 0; mx = max( mx, p[i-1] - beg ); beg = 0; }
    }
    printf( "%d\n", mx );
	return 0;
}