How to make a function which has continuous argument (without any gap or commas)

[mara]

I'm closing this thread as it's an almost word-for-word duplicate of this same question yesterday:

How to make function which can read an argument without any gap or comma?

I am new to R and i want to make a function where i want my function to read my input as ABCDEF.... Please tell me how can i make this function where my argument is like this. I am able to make a function with input like this A,B,C,D,E,F...