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.Scanner;
class Main{
    public static void main(String[]arge){
        Scanner sc=new Scanner(System.in);
        
        int n=sc.nextInt(); 
        int[] R = new int[n];
                
        for(int i=0; i<n; i++){
            R[i]=sc.nextInt();
            } 
        int answer=R[1]-R[0];
        for(int i=1; i<n; i++){
            int min=1000000000;
            for(int j=0; j<i; j++){
                if(R[j]<min){
                    min=R[j];
                }
            }
            if(answer<R[i] - min)
                answer=R[i]-min;
        }
        System.out.println(answer);
    }
}