I'm trying to remove the 3rd and 4th letter in every string in a column of a DF. It's a different letter each time, so I don't know how to use regex to do it.
For example, if my DF is:

```
{A                     B           C

'32435'                3           5

'45243'                2           4}

```

I'm trying to turn it into:

```
{A                     B           C

'325'                  3           2

'453'                  2           4}

```