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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;


public class Contest
{
	public static void Main()
	{
		int[] a = Array.ConvertAll(Console.ReadLine().Split(' '), new Converter<string,int>(s => int.Parse(s)));

		int[] b = Array.ConvertAll(Console.ReadLine().Split(' '), new Converter<string,int>(s => int.Parse(s)));
//		int[] c = Array.ConvertAll(Console.ReadLine().Split(' '), new Converter<string,int>(s => int.Parse(s)));
//		int[] d = Array.ConvertAll(Console.ReadLine().Split(' '), new Converter<string,int>(s => int.Parse(s)));
/*
		int n = a[0];
		int[][] e = new int[n][];
		for(int i=0; i<n; i++) e[i] = Array.ConvertAll(Console.ReadLine().Split(' '), new Converter<string,int>(s => int.Parse(s)));
*/

		int cnt = b[0];
		for(int i=1; i<a[0]; i++){
			if(0<(b[i]-b[i-1])) cnt += b[i]-b[i-1];
			
			
		}

		string ans = (cnt).ToString();

		Console.WriteLine(ans);
	}
	
	private static int calc_main(int[] a,int[] b,int[] c,int[] d) {



		return 0;
	}




}