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 (GCC 5.4.1) (judge verdict: Runtime Error)

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main(void)
{
  int N,h[100];
  int i,j,k=0,cnt=0,water=0,flg;
  scanf("%d",&N);
  for(i=0;i<N;i++)
    scanf("%d",h[i]);
  
  while(flg!=N)
  {
    flg = 0;
  	for(j=0;j<N;j++){
    	if(h[j]!=0){
          h[j]--;
          water++;
        }
        for(k=j+1;k<N;k++){
          if(h[k]!=0){
            h[k]--;
            water++;
          }
        }
    }
      if(water>0){
        cnt++;
        for(i=0;i<N;i++){
          if(h[i]==0)
            flg++;
        }
      }
  }
  printf("%d\n",cnt);
  return 0;
}