Parsing a number

[Aleksandar1]

I need to separate the number 205123456789999911 into 3 parts, according to the principle of the first 3 characters, then the next 13, then the last 2, but I encounter a problem when this part of 13 characters has less than 13 because it is entered by the end user,my workflow later adds a 0 in front of the middle number to get 13 characters, any advice is welcome

I know that I extract the first 3 and the last 2 characters using the left and right formula, but I don't have a solution for this in the middle

[Aleksandar1]

That formula for middle number is everything i needed.

Thanks!