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.util.Scanner;

public class Main {

	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int t = sc.nextInt();
		int[] R = inpNum(t);

		int mp = maxProfit(R);
		System.out.println(mp);
		sc.close();
	}

	private static int maxProfit(int[] R) {
		int max_p = 0;

		for(int i = 0; i < R.length - 1; i++) {
			for(int j = i + 1; j < R.length; j++) {

				if (i == 0 && j == 1) {
					max_p = R[j] - R[i];
				} else {
					max_p = Math.max(max_p, R[j] - R[i]);
				}

			}
		}
		return max_p;
	}

	private static int[] inpNum(int n) {
		int[] nums = new int[n];

		for (int i = 0; i < n; i++) {
			nums[i] = sc.nextInt();
		}
		return nums;
	}
}