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.*;

/**
 * D
 */
public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        int max_v, min_v;
        int n = sc.nextInt();

        int array[] = new int[n];

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

        sc.close();

        max_v = array[1] - array[0];
        min_v = array[0];

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

            if(array[i] - min_v > max_v) {
                max_v = array[i] - min_v;
            }

            if(array[i] < min_v) {
                min_v = array[i];
            }

        }

        System.out.println(max_v);

    }
}