*[Related](https://codegolf.stackexchange.com/questions/94519/output-a-strings-cumulative-slope)*

Explanation
===========

Given a string such as `DCBA`, convert it to ASCII ordinals, such as `68 67 66 65`. Then, take the differences between each value, eg `67 - 68 = -1, 66 - 67 = -1...` giving `-1 -1 -1` Now as long as there is more than 1 left over value, repeat getting the differences.

For a 3 letter string, your pathway should be similar to

```
A   F   G
65  70  71
-5  -1
-4

```

And for a 5 letter string...

```
B   A   C   E   D   F
66  65  67  69  68  70
1   -2  -2  1   -2
3   0   -3  3
3   3   -6
0   9
-9

```

The Challenge
=============

Take a string input through any [Standard IO Method](http://meta.codegolf.stackexchange.com/questions/2447/default-for-code-golf-input-output-methods), and output the value of the cumulative delta as described above.

Test Cases
==========

```
input: cows
output: 8

input: helloworld
output: 905

input: aaaaaa
output: 0

input: abcdef
output: 0

input: ghfie
output: 20

input: CODEGOLF
output: 185

```

Rules
=====

* [Standard Loopholes Apply](http://meta.codegolf.stackexchange.com/questions/1061/loopholes-that-are-forbidden-by-default)
* The input will only consist of ASCII letters that are either all uppercase or all lowercase
* Your code MUST work for both lower and upper case.
* The input will contain at least 2 characters.
* The output may be positive or negative, as long as its absolute value matches the absolute value of the cumulative delta.
* This is marked as [code-golf](/questions/tagged/code-golf "show questions tagged 'code-golf'"), as such, shortest answer in bytes wins!