A valid encoding of an array of `words` is any reference string `s` and array of indices `indices` such that:

- `words.length == indices.length`
- The reference string `s` ends with the `'#'` character.
- For each index `indices[i]`, the substring of `s` starting from `indices[i]` and up to (but not including) the next `'#'` character is equal to `words[i]`.

Given an array of `words`, return the length of the shortest reference string `s` possible of any valid encoding of `words`.

Example 1:

    Input: words = ["time", "me", "bell"]
    Output: 10
    Explanation: A valid encoding would be s = "time#bell#" and indices = [0, 2, 5].
    words[0] = "time", the substring of s starting from indices[0] = 0 to the next '#' is underlined in "time#bell#"
    words[1] = "me", the substring of s starting from indices[1] = 2 to the next '#' is underlined in "time#bell#"
    words[2] = "bell", the substring of s starting from indices[2] = 5 to the next '#' is underlined in "time#bell#"

Example 2:

    Input: words = ["t"]
    Output: 2
    Explanation: A valid encoding would be s = "t#" and indices = [0].

Constraints:

- `1 <= words.length <= 2000`
- `1 <= words[i].length <= 7`
- `words[i]` consists of only lowercase letters.