Problem:
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Maximum Profit

You can obtain profits from foreign exchange margin transactions. For example, if you buy 1000 dollar at a rate of 100 yen per dollar, and sell them at a rate of 108 yen per dollar, you can obtain (108 - 100) × 1000 = 8000 yen.

Write a program which reads values of a currency $R_t$ at a certain time $t$ ($t = 0, 1, 2, ... n-1$), and reports the maximum value of $R_j - R_i$ where $j > i$ .

Input

The first line contains an integer $n$. In the following $n$ lines, $R_t$ ($t = 0, 1, 2, ... n-1$) are given in order.

Output

Print the maximum value in a line.

Constraints

$2 \leq n \leq 200,000$

$1 \leq R_t \leq 10^9$

Sample Input 1

6
5
3
1
3
4
3

Sample Output 1

3

Sample Input 2

3
4
3
2

Sample Output 2

-1

Solution in JAVA (judge verdict: Wrong Answer)

// ALDS1_1_D Maximum Profit
import java.io.*;

class Main {
   public static void main(String[] args) {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

      try {
         int n = Integer.parseInt(br.readLine());
         int[] R = new int[n];
         for (int i = 0; i < n; i++) {
            R[i] = Integer.parseInt(br.readLine());
         }
         System.out.println(max(R));
      }
      catch (Exception e) {
         e.printStackTrace();
      }
   }
   static int max(int[] R) {
      int max = 0;
      for (int i = 0; i < R.length - 1; i++) {
         for (int j = i + 1; j < R.length; j++) {
            if (max < R[j] - R[i]) {
               max = R[j] - R[i];
            }
         }
      }
      return max;
   }
}