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;

public class Main{


	public static void main(String[] args){

		int n;

		Scanner scan=new Scanner(System.in);
		n=scan.nextInt();
		int[] box=new int[n];
		int max=-1000000000;
		int min=1000000000;

		for(int i=0;i<n;i++){
		box[i]=scan.nextInt();
		}

		for(int i=0;i<n-1;i++){

			if(min>box[i]){
			for(int j=i+1;j<n;j++){
				if(box[j]-box[i]>0&&min>box[i])min=box[i];
				if(max<box[j]-box[i])max=box[j]-box[i];
			}
			}//if(min>box[i])
		}
		System.out.println(max);



		scan.close();

	}

}