Hackety Hacking Problem Factorial

Problem Statement

You have a word each made up of different letter no letter repeated.You have been given the length of the word.Now the problem is that you have to print the number of ways in which the letters can be arranged to return a new word. For Example: Word Length=3 take a word "bat" It can be written in 6 different ways: abt atb bat bta tab tba

So you have to write a program which takes the word length as the input from the user,And prints the number of ways in which they can be arranged.