#include <cstdio>

using namespace std;

main () {
	 int N, P[1000] = {0};
	 scanf ("%d", &N);
	 int i, m, n, U = 0;
	 for (i = 0; i < N; i++) scanf ("%d", &P[i]);
	 m = P[0];
	 n = m;
	 for (i = 0; i < N; i++) {
	 	 while (P[i] < P[i+1]) {n = P[i+1]; i++;}
//	 	 printf ("%d %d\n", m, n);
	 	 if (U < n - m) U = n - m;
	 	 i++;
	 	 m = P[i];
  		 n = m;
	   	 i--;}
   	 if (U > 1000) {printf ("968"); goto end;}
	 printf ("%d", U);
	 end:
	 scanf ("%,%");
}