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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <sstream>
using namespace std;
#include <bits/stdc++.h>
#include<utility>
#include <algorithm>
#include<iterator>
#define  go return 0
#define rep(i,n) for(int i=0;i<n;++i)
#define all(v)   ((v).begin()), ((v).end())
#define F first
#define S second
#define p_b push_back
#define m_p make_pair
typedef long long ll;
typedef double db;
typedef vector<ll> ve;
typedef pair<int, int> pa;
typedef vector<pair<int,int> > vepa;
typedef map<int, int> mp;
const ll N=1e6+5;
ll arr[N],A[N],ARR[N]  ;
bool visited[N]={};
ll cnt[N]={};
bool f;
int main()
{
    int n,count(0);
    cin>>n;
    rep(i,n&&cin>>arr[i]);
    for(int i=0;i<n;)
    {
        if(arr[i]!=0)
            count++;
        else
        {
            i++;
            continue;
        }
        for(int j=i;j<n;j++)
        {
            if(arr[j]<=0)
                break;
            else
                arr[j]--;
        }
    }
    cout<<count;



go;
}