Jquery. Script changes value in input field. Than based on value in the input field need to execute if statement

Jquery. Script changes value in input field. Than based on value in the
input field need to execute if statement

Here is example jsFiddle
If enter something in First input, then value in the Second and Third
input becomes 1 (one).
Then if value in Third input is > 0 then do something, for
examplealert("Test");
But this if statement does not work. For my eyes value in Third input is 1
(one), but for script seems the value in Third input is empty
How to get execute if statement?