Problem:
Score : 300 points

Problem Statement

In a flower bed, there are N flowers, numbered 1,2,......,N. Initially, the heights of all flowers are 0.
You are given a sequence h=\{h_1,h_2,h_3,......\} as input. You would like to change the height of Flower k to h_k for all k (1 \leq k \leq N), by repeating the following "watering" operation:

Specify integers l and r. Increase the height of Flower x by 1 for all x such that l \leq x \leq r.

Find the minimum number of watering operations required to satisfy the condition.

Constraints

1 \leq N \leq 100

0 \leq h_i \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
h_1 h_2 h_3 ...... h_N

Output

Print the minimum number of watering operations required to satisfy the condition.

Sample Input 1

4
1 2 2 1

Sample Output 1

2

The minimum number of watering operations required is 2.
One way to achieve it is:

Perform the operation with (l,r)=(1,3).

Perform the operation with (l,r)=(2,4).

Sample Input 2

5
3 1 2 3 1

Sample Output 2

5

Sample Input 3

8
4 23 75 0 23 96 50 100

Sample Output 3

221

Solution in Kotlin (1.0.0) (judge verdict: Runtime Error)

private val scanner = java.util.Scanner(System.`in`)

private fun readInts(n: Int) = Array(n) { scanner.nextInt() }
private fun readLongs(n: Int) = Array(n) { scanner.nextLong() }
private fun readLineInts() = readLine()!!.split(" ").map { it.toInt() }.toTypedArray()
private fun readLineLongs() = readLine()!!.split(" ").map { it.toLong() }.toTypedArray()

fun main(args: Array<String>) {
    val N = readLine()!!.toInt()
    val h = readInts(N).toList()

    var count = 0
    val flowers = h.toMutableList()
    for (w in 0 until h.max()!!) {
        val line = flowers.joinToString("") { if (it > 0) it.toString().replace("0", "A") else it.toString() }
        count += line.split("0").filter { it.trim() != "" }.size
        for ((index, value) in flowers.withIndex()) {
            if (value > 0) flowers[index]--
        }
    }

    println(count)
}