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(input) {
  input = input.split("\n");
  var values = input.map(function(v) { return parseInt(v); });

  var min = Number.MAX_VALUE, val = -Number.MAX_VALUE;
  var N = values[0];
  for (var i = 1; i <= N-1; i++) {
    if (min >= values[i]) {
      min = values[i];
    }
    if (values[i+1] - min >= val) {
      val = values[i+1] - min;
    }
  }
  console.log(val);
  return val;
}
main(require("fs").readFileSync("/dev/stdin", "utf8"));