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.io.*;
import java.util.*;



public class Main{
    public static void main(String[] args)throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str;
                    
        str = br.readLine();
        int x = Integer.parseInt(str.trim());
        int[] line = new int[x];

        for(int i=0;i<x;i++){
            line[i] = Integer.parseInt(br.readLine());
        }

        int ans = -1000000000;
        int Ri = line[0];
        for(int i=1;i<x;i++){
            if(line[i] - Ri >ans){
                ans = line[i] - Ri;
            }
            if(Ri > line[i]){
                Ri = line[i];
            }

        }

        System.out.println(ans);

        br.close();
    }

    
}