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 Go (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// 挿入ソート
func main() {

	// var num int
	// // fmt.Scanは自動で空白区切で読み込む
	// fmt.Scan(&num)
	// nums := make([]int, num)
	// for i := range nums {
	// 	fmt.Scan(&nums[i])
	// }
	scanner := bufio.NewScanner(os.Stdin)
	var num int
	scanner.Scan()
	num, _ = strconv.Atoi(scanner.Text())
	nums := make([]int, num)
	for i := range nums {
		scanner.Scan()
		nums[i], _ = strconv.Atoi(scanner.Text())
	}

	maxDiff := 1 - 10*10*10*10*10*10*10*10*10 - 1
	min := nums[0]

	for i := 1; i < num; i++ {
		diff := nums[i] - min
		if maxDiff < diff {
			maxDiff = diff
		}
		if nums[i] < min {
			min = nums[i]
		}
	}

	fmt.Println(maxDiff)
}