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.Scanner;

public class Main{

	public static void main(String args[]){
		new Main().mainrun();
	}

	private Scanner scan;
	private int n;

	public void mainrun() {
		scan = new Scanner(System.in);

		n = scan.nextInt();

		int max = Integer.MIN_VALUE;
		int min = scan.nextInt();
		
		for(int i = 1;i < n;i++) {
			int R = scan.nextInt();
			
			max = Math.max(max, R - min);
			
			min = Math.min(min, R);
		}

		System.out.println(max);
	}
}