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

// Dynamic Programming //
// minv = R[0]
// for j が 1 から n-1 まで
//   maxv = (maxv と R[j]-minv のうち大きい方)
//   minv = (minv と R[j] のうち小さい方)

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

// Scan Standard Input
var sc = bufio.NewScanner(os.Stdin)

func nextLine() string {
	sc.Scan()
	return sc.Text()
}

func main() {
	count, _ := strconv.Atoi(nextLine())

	n0, _ := strconv.Atoi(nextLine())
	minv := n0
	maxv := math.MinInt32

	for i := 1; i < count; i++ {
		n, _ := strconv.Atoi(nextLine())

		if maxv < n-minv {
			maxv = n - minv
		}

		if minv > n {
			minv = n
		}
	}

	fmt.Println(maxv)
}