#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e18 + 5;
const long long mod = 1e9 + 7;
const long long N = 2e5 + 314;
const long double pi = 3.1415926535897932384626433832795;
void solve() {
  long long n;
  cin >> n;
  vector<long long> v(n);
  long long ans = 0;
  for (long long i = 0; i < n; i++) cin >> v[i];
  for (long long i = 1; i < n; i++) ans = max(ans, v[i] - v[i - 1]);
  cout << ans;
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long t = 1;
  while (t--) solve();
}
