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)

function main() {
  const n = parseInt(input.shift(), 10);
  const prices = input.map(function(x) {
    return parseInt(x, 10);
  });
  let max = -1000000000;
  let min = prices[0];
  for (let i = 1; i < prices.length; i++) {
    min = Math.min(min, prices[i - 1]);
    max = Math.max(max, prices[i] - min);
  }
  console.log(max);
}

var input = '';
process.stdin.resume();
process.stdin.setEncoding('utf8');
process.stdin.on('data', function(chunk) {
  input += chunk;
});
process.stdin.on('end', function() {
  input = input.split('\n');
  input.pop();
  main();
});