#include <algorithm>
#include <iostream>
#include <utility>
#include <vector>
using namespace std;
class Soultion {
private:
std::vector<int> prices_;
public:
explicit Soultion(std::vector<int>&& prices) {
prices_ = std::forward<std::vector<int>>(prices);
}
int getMaxProfit() {
int max_profit = 0;
int min_prices = prices_[0];
for (auto p : prices_) {
max_profit = std::max(max_profit, p - min_prices);
min_prices = std::min(min_prices, p);
}
return max_profit;
}
};
int main() {
int n;
std::cin >> n;
std::vector<int> prices;
while (n-- >= 1) {
int p;
std::cin >> p;
prices.push_back(p);
}
std::cout << Soultion(std::move(prices)).getMaxProfit();
}
// 64 位输出请用 printf("%lld")