Minimum Changes to Non-decreasing Array

You are given an array of integers. Your task is to determine the minimum number of modifications required to make the entire array non-decreasing. A modification consists of changing an element's value. In each modification, you can change an element to any integer value.

For example, given the array [4, 2, 3, 1, 5], you can change it in such a way that it becomes non-decreasing with 2 modifications. Similarly, for [1, 2, 3, 5, 4, 6], only 1 modification is needed.

The problem requires an optimal strategy that minimizes the number of changes while ensuring the array remains non-decreasing, i.e., for every valid index i, a[i] <= a[i+1] holds.

The solution must process input from standard input (stdin) and produce the result on standard output (stdout).

inputFormat

The first line contains an integer n representing the number of elements in the array.

The second line contains n space-separated integers representing the array.

outputFormat

Output a single integer representing the minimum number of modifications required to make the array non-decreasing.

5
4 2 3 1 5

2