#include <cstdio>

const int MAXN = 2000;

int n, p[MAXN];

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