Minimum Operations to Transform Array

Given an array of length \(n\) initially filled with zeros, you are allowed to perform the following operation:

• Select a contiguous subarray \([l, r]\) and add a positive integer \(x\) to all elements in that range.

The operations have a restriction: for any two operations, their intervals must either be completely disjoint or one must be completely contained within the other.

Given a target array \(a\), determine the minimum number of operations required to transform the original zero array into \(a\).

Hint: The answer can be computed as \(a_0 + \sum_{i=1}^{n-1} \max(0, a_i - a_{i-1})\).

inputFormat

The first line contains an integer \(n\), the length of the array.

The second line contains \(n\) space-separated integers representing the target array \(a\).

outputFormat

Output a single integer representing the minimum number of operations required.

sample

3
1 2 3

3