Problem:
MathJax.Hub.Config({ tex2jax: { inlineMath: [["$","$"], ["\\(","\\)"]], processEscapes: true }});

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.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;
import java.util.Arrays;

class Main{
	public static void main(String[] args)throws Exception{
		BufferedReader br = 
			new BufferedReader(new InputStreamReader(System.in));
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int[] numbers = new int[n];
		for(int i = 0; i < n; i++){
		    numbers[i] = scanner.nextInt();
		}
		int min = numbers[0];
		long max = -999999999999l;
		for(int i = 1; i < n; i++){
			if(numbers[i] - min > max){
				max = numbers[i] - min;
			}
			if(numbers[i] < min){
				min = numbers[i];
			}
		}
		System.out.println(max);
	}
}