i am creating a custom CustomerID by getting the first double characters of first name and last name taken from textboxes as following: 

```
 string CustomID = (FirstNameTxtbox.Value.Substring(0, 2) + LastNametxtbox.Value.Substring(0, 2));

```

in order to avoid a Duplicated CustomerID
i am trying to:

get the 5th value which is the int since the first 4 values are characters. and then increase it by 1.

my attempt: 

```
string s =  cmd.CommandText= " Select MAX(CustomerID) from Customers";
string CustomID = (FirstNameTxtbox.Value.Substring(0, 2) + LastNametxtbox.Value.Substring(0, 2) + (Convert.ToInt32(s)+1)) ;

```

example: 

First name= Mak  

last name = shima 

CustomerID = MASH1 

next value will be e.g KAAR2