Contest Duration: - (local time) (100 minutes) Back to Home
C - Grand Garden /

Time Limit: 2 sec / Memory Limit: 1024 MB

### 問題文

• 整数 l,r を指定する。l \leqq x \leqq r を満たすすべての x に対して、花 x の高さを 1 高くする。

### 制約

• 1 \leqq N \leqq 100
• 0 \leqq h_i \leqq 100
• 入力はすべて整数である。

### 入力

N
h_1 h_2 h_3 ...... h_N


### 入力例 1

4
1 2 2 1


### 出力例 1

2


「水やり」操作の回数は 2 回が最小です。 以下が一つの例です。

• (l,r)=(1,3) の「水やり」操作を行う。
• (l,r)=(2,4) の「水やり」操作を行う。

### 入力例 2

5
3 1 2 3 1


### 出力例 2

5


### 入力例 3

8
4 23 75 0 23 96 50 100


### 出力例 3

221


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