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.util.Scanner;
public class Main{
    public static void main(String[] args){
        
        int n;
        int[]R;
        
        Scanner scan = new Scanner(System.in);       
        n = scan.nextInt();
        R = new int[n];
        
        for(int i=0 ; i < n;i++) {
            R[i] = scan.nextInt();
        }
        
        
         int answer = R[1] - R [0] ; 
         int min = R[0];
        
        for (int i = 1 ; i < n; i++){
                    if (R[i] - min > answer){ 
                    answer = R[i] - min;
                   }
                   if(min> R[i]){
                    min = R [i];
                   }
                

            } 

       
        System.out.println(answer);
    }
  }