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: Accepted)

import java.util.*;
public class Main{
   public static void main(String[] args) {
   Scanner sc = new Scanner(System.in);
   
   int n = Integer.parseInt(sc.nextLine());
   int[] arr = new int[n];
   
   for(int i = 0; i < n; i ++) {
      arr[i] = Integer.parseInt(sc.nextLine());
   }
   
   int min = arr[0];
   int maxP = arr[1] - arr[0];
   
   for(int i = 1; i < n; i ++) {
      int dif = arr[i] - min;
      if(dif > maxP) {
         maxP = dif;  
      }
      if(arr[i] < min) {
         min = arr[i];
      }
   }
   
   System.out.println(maxP);
    
   }//main
}