Arko is very fond of permutations. He can easily calculate the number of **n** length permutations. (In which permutations there contained **n** numbers from **1** to **n** are called **n** length permutations. (**2, 1, 3, 4**) is called a **4** length permutations.). So his teacher give him a tricky problem on permutations. He has to calculate the number of **n** length permutations where **r** specific values will be in same order.

This is a companion discussion topic for the original entry at https://toph.co/p/arko-and-special-permutations