I want to handle functions execute order to using callbacks. Actually I'm learning Node.js. Because of its async, It's difficult to me to handle process. Anyway, There are 3 function that has callback, 

```
function first(callback){
    console.log("First");
    callback;
}

function second(callback){
    console.log("Second");
    callback;
}

function third(callback){
    console.log("Third");
}

// Let's run it!

first(second(third));

// result 

Second
First

```

I don't understand why the result is. I expected below:

```
First
Second
Third

```

What's problem? How could I do it correctly? In Node.js, Do people usually handle functions excute order by using callbacks? that is little complex I think. Isn't it?