Hi, 

Going through the '<-' description in 'learnouahaskell' it says - 

" If we have a Maybe String and we bind it with <- to a variable, that variable will be a String"

so if you write 

do
str <- Just "3"

str should be of type 'String'. My question is how do I return "34" by concatenating it to "4" because the following line of code fails - 

---
do
str <- Just "3"
return str++"4"::Maybe String
---

or for that matter how can I return/print just the value of str from this do block ?

Thanks,
Shishir