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: Wrong Answer)

import java.util.*;
                    
class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();
        int[] R = new int[t];
        int i, j, a, bnf;
        R[0] = sc.nextInt();
        R[1] = sc.nextInt();
        int max = R[1];
        int min = R[0];
        bnf = max - min;
                    
        for(i=2; i<t; i++){
            R[i] = sc.nextInt();
            if(bnf<0 && R[i]<R[i-1]){
                a = R[i] - R[i-1];
                if(bnf < a) bnf = a;
            }else{
                if(min>R[i]){ 
                    a = max - min;
                    if(bnf<a) bnf = a;
                    min = R[i];
                    max = R[i];
                }else if(max<R[i]) max = R[i];
            }
        }
        a = max - min;
        if(bnf<a) bnf = a;
                     
        System.out.println(bnf);
    }
}