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)

import java.util.Scanner;
class Main {
   public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		int input = scan.nextInt();
		int[] num = new int[input];
		
		for(int c = 0; c < input; c++){
			num[c] = scan.nextInt();
		}
		
		int max = num[1] - num[0];
		
		for(int j = 1; j < input - 1; j++){
			for(int i = 0; i< j - 1; i++){
				max = Math.max(max, num[j] - num[i]);
			}
		}
		
		int min = num[0];
		for(int j = 1; j < input - 1; j++){
			max = Math.max(max, num[j] - min);
			min = Math.min(min, num[j]);
		}
		
		System.out.println(max);
	}
}