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: Time Limit Exceeded)

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) {
		final int[] list = getList();
		final int diff = getMaxDiff(list);
		
		System.out.println(diff);
	}
	
	public static int getMaxDiff(int[] list) {
		int maxDiff = list[1] - list[0];
		int diff;
		
		for (int i = 2; i < list.length; i++) {
			for (int j = 0; j < i; j++) {
				diff = list[i] - list[j];
				if (maxDiff < diff) maxDiff = diff;
			}
		}
		
		return maxDiff;
	}
	
	public static int[] getList() {
		int[] list = null;
		
		try {
			final BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
			final int n = Integer.parseInt(reader.readLine());
			list = new int[n];
			for (int i = 0; i < n; i++) {
				list[i] = Integer.parseInt(reader.readLine());
			}
			reader.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		return list;
	}
}