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.*;

public class Main {
	public static void main(String[] a) {
		Scanner input = new Scanner(System.in);
		int loop = input.nextInt();
		int max = -1;
		int[] num = new int[loop];

		if (loop >= 2 && loop <= 200000) {

			for (int i = 0; i < loop; i++) {
				int newNum = input.nextInt();

				if (newNum >= 1 && newNum <= 1000000000) {
					num[i] = newNum;
					if (i == 1)
						max = num[1] - num[0];

					if (i > 0) {

						for (int j = 0; j < i; j++) {
							max = newNum - num[j] >= max ? newNum - num[j]
									: max;
						}
					}
				}

			}

			System.out.println(max);

		}

	}

}