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.io.*;
                
class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(br.readLine());
        int[] R = new int[t];
        int i, j, a, bnf;
        R[0] = Integer.parseInt(br.readLine());
        R[1] = Integer.parseInt(br.readLine());
        bnf = R[1] - R[0];
                
        for(i=2; i<t; i++){
            R[i] = Integer.parseInt(br.readLine());
                for(j=0; j<i; j++){
                    a = R[i] - R[j];
                if(bnf < a) bnf = a;
            }
        }
                 
        System.out.println(bnf);
    }
}