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 Julia (0.5.0) (judge verdict: Wrong Answer)

function main()
  
  N = parse(Int,readline())
  h = map(x -> parse(Int,x), split(readline()))
  
  ans = 0
  check = 1
  save = 0
  
  for i in 1:N
    if N == 1
      ans = h[1]
    elseif i < N && h[i] > h[i+1]
      ans += h[i] - save
      if h[i+1] - save <= 0
        save = 0
      else
        save = h[i+1]
      end
    elseif i == N && h[i-1] < h[i]
      ans += h[i] - save
    end
  end
  
  println(ans)
  
end

main()