You are given an array of `n` strings `strs`, all of the same length.

The strings can be arranged such that there is one on each line, making a grid. For example, `strs = ["abc", "bce", "cae"]` can be arranged as:

    abc
    bce
    cae

You want to delete the columns that are not sorted lexicographically. In the above example (0-indexed), columns 0 (`'a'`, `'b'`, `'c'`) and 2 (`'c'`, `'e'`, `'e'`) are sorted while column 1 (`'b'`, `'c'`, `'a'`) is not, so you would delete column 1.

Return the number of columns that you will delete.

Example 1:

    Input: strs = ["cba","daf","ghi"]
    Output: 1
    Explanation: The grid looks as follows:
      cba
      daf
      ghi
    Columns 0 and 2 are sorted, but column 1 is not, so you only need to delete 1 column.

Example 2:

    Input: strs = ["a","b"]
    Output: 0
    Explanation: The grid looks as follows:
      a
      b
    Column 0 is the only column and is sorted, so you will not delete any columns.

Example 3:

    Input: strs = ["zyx","wvu","tsr"]
    Output: 3
    Explanation: The grid looks as follows:
      zyx
      wvu
      tsr
    All 3 columns are not sorted, so you will delete all 3.

Constraints:

- `n == strs.length`
- `1 <= n <= 100`
- `1 <= strs[i].length <= 1000`
- `strs[i]` consists of lowercase English letters.