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"
)

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Scan()
	// length, _ := strconv.Atoi(sc.Text())

	var min, diff, i int
	for sc.Scan() {
		input, _ := strconv.Atoi(sc.Text())
		if i == 0 {
			min = input
		} else if i == 1 {
			diff = input - min
			if input < min {
				min = input
			}
		} else {
			if diff < input-min {
				diff = input - min
			}
			if input < min {
				min = input
			}
		}
		// fmt.Printf("%d %d\n", min, diff)
		i++
	}
	fmt.Println(diff)
}