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: Wrong Answer)

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


public class Main {
	public static void main(String[] args)throws IOException{
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

		int readNumOfData = Integer.parseInt(in.readLine());
		int[] numArr = new int[readNumOfData];
		int maxPro=0, temp;

		try{
			for(int i=0; i<readNumOfData; i++){
				numArr[i] = Integer.parseInt(in.readLine());
			}

			for(int j=0; j<readNumOfData-1; j++){

				if(j==0){
					maxPro = numArr[j+1] - numArr[j];
					continue;
				}
				temp = numArr[j+1] - numArr[j];
				if(maxPro < temp){
					maxPro = temp;
				}
			}

			System.out.println(maxPro);
		} catch(Exception e){
			e.printStackTrace();
		}
	}
}