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 JavaScript (judge verdict: Accepted)

var input = require('fs').readFileSync('/dev/stdin', 'utf8');
var Arr=input.split("\n").map(Number); 

var N = Arr[0];

var getMaxProfit = (num,array) => {
    var minR = array[1];
    var maxR = array[2] - array[1];
    
    for(let i =2; i <= num; i++){
        maxR = (maxR<(array[i]-minR)) ? (array[i]-minR) : maxR;
        minR = (minR < array[i]) ? minR : array[i];
    }
    
    return maxR;
}

console.log(getMaxProfit(N,Arr));